cleaning diesel fuel tank sailboat

Practical Boat Owner

• Digital edition

Cleaning a diesel tank: a practical guide

• Richard Barnard
• January 19, 2023

Richard Barnard braves the mess and overcomes key challenges for the satisfaction of a clean fuel tank, free from sediment and sludge

Left: Sludge in the tank by one of the baffles. Right: the diesel feed pipe after cleaning. Credit: Richard Barnard Credit: Richard Barnard

There can’t be many of us who sail boats with engines who haven’t experienced the dying clunks of our engine as it grinds to a halt.

The most common reason is a blockage in the fuel system, caused by sediment in the fuel, or the dreaded diesel bug clogging the fuel line.

You can minimise these risks by using a filter funnel and adding anti-bug chemicals whenever you fill up your tank.

I’ve always taken these precautions and managed to avoid problems with fuel until this season, when a particularly rough sea stirred up trouble in my tank.

After I got home under sail, I checked the primary fuel filter and found it jammed solid with a brown, jelly-like substance, with some grit within it.

The tank is ready to disconnect and move. Credit: Richard Barnard

The tank drain hole is located in a front corner of the tank, directly below the bottom of the fuel feed pipe.

Nothing came out of this drain, but I was able to suck it clear using a hand pump, which pulled out more of the jellied sediment.

There was clearly a major problem that changing the fuel filter was never going to resolve and I’d have to clean out the tank.

With the drain hole now clear I drained off the 40lt of diesel sitting in the 250lt tank, grateful that I hadn’t recently filled it!

Tank top beneath the saloon seat. Credit: Richard Barnard

By removing the fuel gauge unit on the tank top, I created a 2in diameter hole through which I could insert a small torch and squint.

I could also insert a length of bamboo and feel the bottom of the tank. I could see, and feel, sludge about half an inch deep.

Three key challenges when cleaning a diesel tank

At 250lt (65gal) the tank was large and difficult to remove from the boat. It was sited beneath a saloon seat with limited access to its top.

There were no access hatches to allow inspection of the interior or cleaning.

Given the absence of hatches it’s likely the tank had never been properly cleaned since it was fitted, and that the sediment was just an accumulation of decades of dirt in the fuel and some bacterial activity.

Tank freed and holes marked. Credit: Richard Barnard

Whatever the reasons, I would have to fit three hatches in the tank top, above the three baffled sections, to allow access for cleaning.

To do that I’d have to release the tank and slide it into the centre of what was fortunately a large engine room bilge area.

I calculated that if I could find hatches of about 5in (125mm) in diameter, I’d be able to fit one above each baffled section of the tank, which would allow me to get my arm in for cleaning.

Cutting the hatch access holes. Credit: Richard Barnard

I should also be able to cut the holes without having to remove the tank completely.

I searched for tank access hatches on the internet, finding the perfect one: an FLB tank inspection hatch, produced by Wema UK.

This is made up of two strong, plastic, circular plates, joined by a central bolt.

Hatch holes cut. Credit: Richard Barnard

By cunning shaping of the lower plate, it is possible to slide the unit into and over the cut hole and tighten the bolt, which pulls the plates together, sealing the top plate with a substantial O-ring.

Before unbolting the tank I marked out the places on the top, between the timber sole bearers, where the hatches should be fitted.

Continues below…

12 diesel bug treatments tested

Diesel bug can clog filters and starve your boat engine of fuel just when you need it most. Can diesel…

How to remove a marine diesel cylinder head step by step

During the summer of the 2019 our Bavaria 39 Tessa Jane began producing black exhaust smoke and suffering a reduction…

How to: troubleshoot your marine diesel fuel system

One of the most common causes of a marine diesel engine not starting is a fuel problem. If you have…

How to service a marine diesel engine in 12 simple steps

It was time to service the marine diesel engine on our Maxi 84 cruiser. Knowing how to diagnose and fix…

Disconnecting and releasing the tank was easy, but sliding it out and securing it in place for working on required a bit of care to ensure I didn’t create any problems with the prop shaft or wiring.

My friendly local metalworker used his skill and stainless steel jigsaw cutting blades to cut the three circular holes and I was then able to have a better look within.

The diesel feed pipe before cleaning. Credit: Richard Barnard

The foul brown sludge lay all over the bottom of the tank, clearly visible through the holes and in the photos taken by my phone as I carefully lowered it into the tank.

To remove this sludge I used a cut milk carton as a scoop, pouring the sludge into a plastic pint glass, which I then periodically lifted out to transfer the sludge into a jerry can.

The sludge being scooped out. Credit: Richard Barnard

It was messy, but it wasn’t long before I could use a big sponge to squeegee the tank, rinsing the sponge in buckets of fresh water.

When it was as clean as I could make it this way, I washed the tank interior with a degreasing agent in water, throwing the liquid all around the inside of the tank and using a long-handled brush to get into all the corners.

Blowing hot air in to dry the interior of the tank. Credit: Richard Barnard

By luck, the tank had orientated itself at a slight angle when I pulled it out, and the drain hole was at its lowest point.

So all this washing out liquid drained away into the sump, from where I could scoop it out later for safe disposal.

Circular access hatches fitted for future cleaning. Credit: Richard Barnard

The tank now looked really clean and I used a hot air gun to start drying out the interior, leaving the tank for a couple of days to completely dry out.

I then fitted the hatches and slid the tank back into place, re-bolting it to its framework and re-connecting it to the fuel filter and engine.

Tank back in place with its new access hatches. Credit: Richard Barnard

The last job was to replace the tank fuel gauge and pour in fresh diesel. With new fuel filters in place, the engine fired up and ran perfectly.

It was so reassuring to know that there was now no risk of future engine failure due to fuel problems, however much the boat might rock around.

The job was very satisfying to do and, if and when I get another boat, I’ll make sure I can inspect inside its fuel tank and ensure it’s clean and free from sediment and sludge.

• Forum Listing
• Marketplace
• Advanced Search
• About The Boat
• Gear & Maintenance
• SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

cleaning diesel fuel tank

• Add to quote

My 18 gallon fuel tank is a contaminated with sludge. I am planning to pump out the remaining contaminated fuel, clean the tank, and replace with clean fuel and a biocide. Has anyone done this before that can provide advice, in particular, what to use to clean the tank. Someone suggested paint thinner. WaltG Miami  

Since diesel cars often add a little petrol (gas) to their winter fuel to thin it for cold starting, I guess it would be a suitable cleaning fluid.  

tank cleanig? are you planning to remove the tank to clean it?? If so I would use a cheap solvent / lacquer thinner to rinse it out and follow up with the high pressure water (i.e. car wash) make sure it is really dry before re-installing and adding fuel IMHO dano  

I just cleaned my diesel tank yesterday. I have had the boat less than 2 years so I was not sure what shape it was in. It is a small tank, about 14 usgal and I took it out which seemed the simplest. I also wanted a look at the bottom to see if there was amy corrosion, it is aluminium. Pumped all of the diesel out and removed it. There was a lot of sludge and black scales on the bottom. We drained it through the fuel level indicator hole. We just rinsed some fresh diesel in it a couple of times and it looks pretty good. Mostly shiney and clean. I was going to use gas but the diesel worked. Only one small spot of corrosion on the bottom and it is not too bad. I am going to coat the bottom with some thing, just not shure what yet. Gary  

We pulled the tank, which is the only way to really do it, so you can invert it to drain it completely. Clean out what you can (and dump it with the other oil waste) then use detergent and water, hot water if you can. Liquid Tide is very good at dissolving oily waste. LesToil, etc. also work fine. Just wash it out, and repeat. Fill the tank partway and shake it to help get the crud dissolved. Then eyeball it and see if that was enough, it often will be. We let it air dry overnight, that was enough but if you are in a hurry a hair dryer, etc. would do the job in a shorter time. If you need to "scrub" where you can't reach, coarse salt (deicing rock salt or koshering salt) in a dry tank acts just like sand, and it can be washed out 100% with water after it has done the job.  

After it's clean, be sure to use a biocide when you refill. That "sludge" you are finding is actually an organic life form that lives in diesel tanks. Also water will stay at the bottom and corrode/rust anything not stainless. It's best to drain the bottom at least every six months. (Or remove it with a pump, drawing from the bottom)  

I have been using two products on my diesel. One claims to emulsify water such that it passes filter and injectors without harming either, the other is supposed to kill the bio-bugs. The result is an increasing amount of "red-stuff" in the bottom of the filter bowls. As it passes through both inline filters, and the engine seems to run fine on it, I am hoping its harmless. Nevertheless, I think its time I pulled out and cleaned the tanks. Any one else seen this?  

Startron I just went to the WM in Ft.Liquordale and found this product by Starbrite called Startron, the Fuel Tank Cleaner. It claims to "clean the fuel tank while rejuvenating old fuel which may be present in the tank". I bought the one gallon size for twenty something bucks. I also pumped out most of the old diesel which had the dark tea color indicating contamination. Will let you know the results with Startron. WaltG Sabre28 Impromptu  

Could you give me more info about this product at WM. I was just on their website but couldnn't find anything about a diesel polishing kit or product 9325. Thanks.  

Go to Star brite - Catalog - Product Detail  

You've got to love some of these additives. http://www.starbrite.com/msdssheets/93108-msds-10-7-06.pdf That one is over 95% naphtha with less than 1/2% of a "proprietary organic compound" which has to be the enzymes in question. IOW a teaspoon of special stuff, in a pint of gasoline stock or paint thinner. I guess the folks who talk about throwing a shot of gasoline in their diesel aren't all wrong.<G>  

I e-mailed Startron (manufactured by Star Bright) and asked if it killed algae: Here is the response I received: "StarTron does not kill anything. It is not a poison like most biocides. We make a Biocide which is called BioDiesel, product # 91216 and is the most effective available at killing microbes. While these type products work great they are poisons and when the fuel is burned the poisons end up in the water. In due time all these products will and should be banned. StarTron is a totally different situation. It is an enzyme and the enzymes will break down these organisms into submicron size particles which are burned through the engine safely. Regular use of StarTron will prevent micro growth. Keep in mind the reason your clothes are washed and end up clean using cold water is one simply fact. Enzymes in the laundry detergent. There are millions of Enzymes and the enzymes we use are specific for our purposes. Yes they are miracles. Keep in mind you are alive as a result of enzymes in your body. Everything you eat is converted and broken down by the millions of enzymes in your body. If StarTron does not do what we say we will be happy to refund your money. !!!! StarTron sounds like hype and bull. I thought that of the product the first time I was exposed to it and read about it. After using and seeing my results and that of 1000's of customers coming back with stories of what the product did for them I became a true believer. Let us know of your results, good or bad." The previous owner of my boat was using Startron, so I had it and have continued using it. I have to say, my fuel looks pretty good. However, it sounds like snake oil to me! How does Startron "not kill anything", while it breaks the critters into particals small enough for the engine to burn, (not to mention, pass through the filters) I would like to ask a chemist if any of Startron's claims can possibly be true. Thoughts?  

http://www.redlineoil.com/ I have used these products for 20 years.  

L124C: Consider this is you will. Neither alcohol nor soap "kill" bacteria, but washing you hands with either product will kill the bacteria--by physically disrupting the cell membranes and "exploding" them. If Startron contains an enzyme that can similarly "eat" the bacteria in your fuel, it could work very nicely. If the makers claimed anything about a "biocide" or "poison" or "killing" then they would be required to regulate the product through the EPA and state agencies as a pesticide--and that's even been a nightmare for companies using longstanding "disinfectants". I'd give it a try, enzymes and phages and other micro-life really can "eat" other microlife and break them down into smaller pieces. Once they're eaten...they can't multiply. Enzymes are used in septic tanks (and holding tanks) for the same purpose, to "eat" paper and feces and break it down into bits of ooze that won't clog things.  

• ?            
• 176.3K members

Top Contributors this Month

Service Locator

• Angler Endorsement
• Boat Towing Coverage
• Mechanical Breakdown
• Insurance Requirements in Mexico
• Agreed Hull Value
• Actual Cash Value
• Liability Only
• Insurance Payment Options
• Claims Information
• Towing Service Agreement
• Membership Plans
• Boat Show Tickets
• BoatUS Boats For Sale
• Membership Payment Options
• Consumer Affairs
• Boat Documentation Requirements
• Installation Instructions
• Shipping & Handling Information
• Contact Boat Lettering
• End User Agreement
• Frequently Asked Questions
• Vessel Documentation
• BoatUS Foundation
• Government Affairs
• Powercruisers
• Buying & Selling Advice
• Maintenance
• Tow Vehicles
• Make & Create
• Makeovers & Refitting
• Accessories
• Electronics
• Skills, Tips, Tools
• Spring Preparation
• Winterization
• Boaters’ Rights
• Environment & Clean Water
• Boat Safety
• Navigational Hazards
• Personal Safety
• Batteries & Onboard Power
• Motors, Engines, Propulsion
• Books & Movies
• Cockpit Confessions
• Communication & Etiquette
• Contests & Sweepstakes
• Colleges & Tech Schools
• Food, Drink, Entertainment
• New To Boating
• Travel & Destinations
• Watersports
• Anchors & Anchoring
• Boat Handling

Clean Your Boat’s Diesel Fuel Tank

Advertisement

Keep your fuel tank – and the fuel in it – spick and span to avoid gunk being sucked up and clogging the system. Here’s how

When the need to clean your fuel tank arises, good access is crucial, such as in this example of a tank and hoses accessible via a large opening in the cockpit deck. Photo: Frank Lanier

Despite the plethora of magic potions and elixirs sold to prevent it, dirty fuel tanks happen. Fuel polishing can help, depending on how often and thoroughly you do it. But at some point, you may need to clean the fuel tank itself of deposits and gunk on the walls and bottom.

Most people think cleaning a fuel tank is a job for professionals, but with the proper tools and planning, many competent DIYers can accomplish the task safely and efficiently. Although each installation will present its own unique set of requirements, here are some general guidelines and safety precautions that can be applied to most tank cleaning jobs.

Our focus here is cleaning diesel fuel tanks only, not gasoline or any other types. There may be some overlapping of tools and techniques, but we can’t ­recommend DIY cleaning gasoline tanks for safety reasons.

In this article, we’ll be covering two likely scenarios: The first is that your tank and the fuel in it need cleaning, however, both can be addressed by fuel polishing. The second is that fuel polishing isn’t enough, so physically accessing the interior and cleaning the tank is required.

Fuel polishing equipment on Tom Neale’s present boat, Chez Nous, a Camano 41. Photo: Tom Neale

Installing fuel tank ports for cleaning can be a daunting proposition. Access is something to note when boat shopping. Photo: Tom Neale

Scenario 1: Fuel Polishing

“Fuel polishing” is simply cleaning the fuel inside your tank by removing it from the tank, cycling it through a filtering system, and returning the cleaned fuel to the tank. This process removes suspended impurities such as dirt or water. Fuel polishing systems can be either permanently mounted or a portable unit.

The primary components of a fuel polishing system are an electric fuel pump, a large fuel filter (such as those by Racor), fuel hoses, and the various fittings and valves needed to connect the intake and return of the polishing system to the fuel tank.

Permanently installed systems are typically separate from the engine fuel supply, although, in some cases, they can be plumbed to use the engine’s primary fuel filter. This is not ideal unless the engine fuel system features selectable dual primary filters, which allows use of the standby or “spare” filter for polishing. Fixed systems can be operated 24/7 if necessary (depending on design) and do not require the engine to be running.

A portable fuel polishing system is connected when actively polishing fuel but removed afterward. Depending on design and tank access ports, a portable system can also be used to assist when cleaning the fuel tank (more on this in a moment).

When designing a fuel polishing system, fuel should be drawn from the bottom of the tank. The fuel pickup for the engine typically stops a couple of inches from the bottom of the tank to avoid sucking up contaminants – the very stuff you want to reach when polishing.

The time required to cycle through all the fuel in your tank will depend on the polishing system components. When purchasing or designing a system, however, three to four hours is a reasonable goal. The system should also be designed to allow easy access for inspection and filter replacement (you’ll be doing this a lot when polishing dirty fuel). As with your primary fuel system, installing a vacuum gauge (to monitor filter condition) is highly recommended.

Don’t have the space or desire to install a polishing system? You can also hire mobile fuel-polishing services to come to your boat.

Remove the fuel

There are several ways you can remove the residual fuel from your tank in preparation for cleaning, but let’s get one thing straight — a shop vac isn’t one of them! Here are six recommended options for getting the fuel out:

• Manual pump, such as diaphragm-style bilge pump. A manual pump means no sparks or potential explosions.
• Length of hose to siphon the fuel out, assuming the receiving container can be positioned beneath the fuel tank. A squeeze-bulb pump (common to outboard gas tanks) will allow you to easily start a siphon. A self-priming jiggler siphon may also work to drain fuel, although it might also clog repeatedly when used to drain a particularly dirty tank.
• A gear fuel pump such as those made by Oberdorfer ( oberdorferpumps.com ).
• If you use an electric pump, ensure it is ignition-protected, suitable for the fuel you are pumping, and located in a well-ventilated area, preferably outside the boat.
• A portable fuel polishing system can also be used to remove unusable fuel.
• A fixed fuel polishing system may also be an option, depending on how it is configured.

Whether you siphon or pump, have someone monitor the receiving container to avoid overflow. An old diesel jerry can works great for this, as it can also be closed and used to safely hold or transport fuel for recycling or disposal. — F.L.

Scenario 2: Tank Cleaning

Your diesel fuel tank should be cleaned at the first sign of contamination, such as irregular running, particulate in the filter parts, or rapid or constant clogging of fuel filters. Particulates and biocontaminants can settle on the bottom of the tank and turn to sludge, which can clog filters and even cause damage to engines and generators if not addressed. The takeaway here? Clean your tank at the first sign of trouble, before things get out of control. If you have a fuel polishing system, use it regularly.

If the tank must be cleaned, common sense dictates removing as much fuel as possible first. The easiest way to do this is by burning the fuel through normal boat use. If you’ve waited until the fuel is unusable, get ready for some pumping, hauling, and possible disposal dilemmas as you work your way toward the dregs at the bottom of the tank.

When it comes to tank cleaning, the more access the better. Ideally your tank has access plates or ports that can removed for internal cleaning and they’re located above a low point in the tank (for easier removal of residue during the cleaning process). If not, you’ll have to use what’s provided (fill hose inlets, vents, fuel gauge sending unit ports) and sprinkle liberally with a little MacGyver-style ingenuity.

If you have a smaller craft and can remove the tank for cleaning, you’ll have additional options, such as rotating it upside down to drain while cleaning. Installing access ports may be an option in some cases, however, due to the safety concerns of cutting into a fuel tank possibly filled with volatile fumes, it’s a job best left for the pros.

A DIY fuel polisher made aboard years ago by Tom Neale, our technical editor. It uses an aluminum sheet, Racor filter, and 12-volt Oberdorfer gear pump. Hoses (not shown) were used to cycle and polish fuel and, with a wand, to vacuum the tank (suction hose) or wash the walls, bottom, and corners (output hose). If the output hose has a smaller diameter than the input hose, the washing pressure is increased. Photo: Tom Neale

Get cleaning

Once the tank is completely drained of fuel (see “Remove the Fuel” on page 85), the real fun begins. With sufficient access, cleaning the tank may be as simple as wiping down the inside with an aqueous degreaser like Simple Green or a similar product from companies like those by CRC (crcindustries.com) or Blaster (blasterproducts.com). In many cases, a rag moistened with diesel fuel will suffice.

Never use solvents or chemicals such as acetone or MEK, which can create a hell’s broth of flammable fumes that aren’t safe to breathe. (We have also not recommended specific chemical “crud-busters.” This is a decision you should make for your specific needs based on product information provided by the manufacturer and other reliable sources.) Although less volatile than gasoline, don’t be complacent when it comes to diesel fuel fumes – particularly as you never know what added chemicals suppliers or workers have introduced into the tank.

Tanks with limited access or internal baffles may require power washing. A standard fan-tipped lance can be used on the more accessible areas, but for the out-of-sight areas, you’ll want to use an extension tipped with a multidirectional tank-cleaning nozzle, such as those available from Bete ( bete.com ), McMaster-Carr ( mcmaster.com ), and Lechler ­( lechlerusa.com ).

An articulating extension for the wand and nozzle may be necessary because of the spray-shadowing effect of the tank’s baffles. Power washing can be very dangerous if the ejected fluid is directed toward your skin, so never point the wand at body parts or other people. A water-resistant endoscope with light (we like the Teslong NTS300 Pro from teslong.com) can be very helpful for locating the crud on the walls, seams, and bottom of the tank and especially around baffles. Also helpful is a handheld light such as StreamLight’s Dualie 3AA with Color-Rite technology (streamlight.com). It has a beam for distance but also a second light, which helps to see colors on murky tank walls.

Diesel deposits can leave a tarry substance stuck to tank bottoms, corners, and other areas. Like road tar, it may be difficult to remove, but it may also break up at unwanted times (such as during a storm or when transiting a rough inlet) and should be removed.

Removal can be accomplished using the power washer mentioned above, which may use water and/or one of the safe crud-cutting solutions on the market. Another option (for removing tar and other dirt) is outfitting the return hose of a portable fuel polishing system with a wand and directing a stream of diesel fuel around tank walls and wherever there is crud. This should wash the crud off if you have a good, powerful pump, particularly when used in conjunction with appropriate cleaning substances.

Sometimes you can remove the tarry substance using the pickup tube from a fuel evacuation pump like a vacuum or by using grabbers. Water and tank crud should ideally drain to a low point under your access port while cleaning, where it can be pumped out. It is important to not leave any tar or other particles in the tank.

After cleaning, dry the interior of the tank with a clean cloth by hand (if it can be reached) or by using extension grippers and rags. You can also provide good ventilation and simply let the tank air dry.

Pressure washing a fuel tank is a dirty job and can cause injury if not done properly, so be sure to follow all manufacturer directions closely and wear all necessary safety gear. Protection from fumes may also be needed depending on your situation, in which case an ignition-protected, industrial-type fan is great for providing additional ventilation.

Fuel tank cleaning safety tips

• Work in a well-ventilated area when cleaning your tank, preferably outside.
• Never clean your tank around any open flames or sparks.
• Wear appropriate protective equipment such as gloves, goggles, or a face mask.
• Follow manufacturer guidelines when using tools or chemicals.
• Be aware of what you’re doing and use common sense! — F.L.

Diesel disposal

Your marina likely has disposal or recycling programs available that can help with disposal of old fuel. If not, there may be other options. Crud-laden diesel fuel can also normally be disposed of through any used oil recycling station (such as those found in automotive parts stores) as long as it’s not contaminated with gasoline or solvents.

Related Articles

The truth about ceramic coatings for boats.

Our editor investigates the marketing claims of consumer-grade ceramic coatings.

Fine-Tune Your Side Scan Fishfinder

Take your side-scanning fishfinder off auto mode, and you’ll be spotting your prey from afar in no time

DIY Boat Foam Decking

Closed-cell foam flooring helps make boating more comfortable. Here’s how to install it on your vessel

Click to explore related articles

Frank Lanier

Contributing Editor, BoatUS Magazine

Capt. Frank Lanier is a SAMS-accredited marine surveyor with over 40 years of experience in the marine and diving industries. He’s an author, public speaker, and multiple award-winning journalist whose articles on boat maintenance, repair, and seamanship appear regularly in numerous marine publications worldwide. Contact him via his YouTube channel “Everything Boats with Capt. Frank Lanier” or at captfklanier.com.

BoatUS Magazine Is A Benefit Of BoatUS Membership

Membership Benefits Include:

Subscription to the print version of BoatUS Magazine

4% back on purchases from West Marine stores or online at WestMarine.com

Discounts on fuel, transient slips, repairs and more at over 1,200 businesses

Deals on cruises, charters, car rentals, hotel stays and more…

All for only $25/year!

We use cookies to enhance your visit to our website and to improve your experience. By continuing to use our website, you’re agreeing to our cookie policy.

Mastering Boat Fuel Tank Cleaning: A Step-by-Step Guide for Smooth Sailing

Imagine being out on the water, enjoying a perfect day of boating when suddenly, your engine sputters and stalls. The culprit? A dirty fuel tank. It’s a common issue that many boat owners face, but fear not – cleaning your boat fuel tank doesn’t have to be a daunting task. In this article, you’ll discover simple yet effective ways to ensure your fuel tank stays clean and your boating adventures remain uninterrupted.

Table of Contents

Picture this: you’re cruising along, the sun shining overhead, and the last thing you want is for a clogged fuel line to ruin the fun. By learning how to properly clean your boat’s fuel tank, you can prevent such mishaps and keep your vessel running smoothly. This guide will walk you through practical steps to maintain a clean and efficient fuel system so that you can focus on enjoying the open water without any worries.

Key Takeaways

• Cleaning your boat’s fuel tank is crucial to prevent engine issues and ensure smooth sailing experiences.
• Recognize signs of a dirty fuel tank like engine stalling, reduced efficiency, unusual sounds, and difficulty starting.
• Neglecting tank maintenance can lead to clogged filters, corrosion damage, fuel contamination, and safety hazards.
• Prioritize safety during the cleaning process by working in ventilated areas, turning off ignition sources, wearing protective gear, handling fuel cautiously, and avoiding open flames.
• Follow a step-by-step guide for cleaning the fuel tank: draining the tank safely, cleaning thoroughly with detergent and water, inspecting components for damage or wear.
• After cleaning, establish a maintenance routine by inspecting regularly, monitoring fuel quality, checking seals/connections, keeping the tank full to minimize condensation, using stabilizers.

Understanding the Importance of Cleaning a Boat Fuel Tank

When it comes to maintaining your boat, ensuring that your fuel tank is clean is crucial. By understanding why cleaning your boat’s fuel tank is essential, you can prevent potential issues and enjoy smooth sailing experiences. Let’s delve into the significance of this maintenance task.

Recognizing Common Signs of a Dirty Fuel Tank

To maintain optimal performance and avoid engine problems, it’s vital to recognize the signs indicating a dirty fuel tank. Here are some common indicators that your boat’s fuel tank may need cleaning:

• Engine Stalling: If your engine frequently stalls or hesitates during operation, it could be due to contaminants present in the fuel from a dirty tank.
• Reduced Fuel Efficiency: A decrease in fuel efficiency or sudden spikes in consumption without any apparent reason may signal impurities affecting the combustion process.
• Unusual Engine Sounds: Strange noises coming from the engine, such as knocking or pinging sounds, can be linked to poor-quality fuel caused by sediment buildup in the tank.
• Difficulty Starting: If you find it increasingly challenging to start your boat’s engine or experience rough idling, it might be time to inspect and clean the fuel tank.

Possible Consequences of Neglecting Tank Maintenance

Neglecting regular maintenance of your boat’s fuel tank can lead to various consequences that impact both performance and safety on the water. Here are some potential outcomes of overlooking tank cleaning:

• Clogged Fuel Filters: Accumulated debris and contaminants in a neglected fuel tank can clog filters, restricting proper fuel flow and potentially causing engine failure.
• Corrosion Damage: Dirt and water buildup inside the tank can promote corrosion, leading to costly repairs or even necessitating replacement of components within the fuel system.
• Fuel Contamination: A dirty fuel tank increases the risk of introducing impurities into your engine, affecting its efficiency and potentially causing long-term damage if not addressed promptly.
• Safety Hazards: In extreme cases, neglecting proper maintenance can result in dangerous situations like unexpected engine failures while out at sea, jeopardizing both your boating experience and safety.

By recognizing these signs and understanding the consequences of ignoring regular cleaning procedures for your boat’s fuel tank, you’ll be better equipped to ensure smooth sailing adventures without unexpected disruptions due to preventable issues with your vessel’s essential systems.

Preparing for the Cleaning Process

Tools and materials needed.

To effectively clean your boat fuel tank, you’ll need a few essential tools and materials. Here’s what you should gather before starting the cleaning process:

• Safety goggles and gloves: Protect yourself from any harmful substances or fumes that may be present in the fuel tank.
• Fuel pump: To remove any remaining fuel from the tank safely.
• Fuel stabilizer: Helps preserve the quality of the fuel during the cleaning process.
• Cleaning solution: Use a specialized cleaner designed for removing residue and contaminants from fuel tanks.
• Brushes and rags: For scrubbing and wiping down the interior of the tank.
• Empty containers: To store removed fuel or cleaning residues properly.

Safety Precautions to Follow

Ensuring your safety is paramount when cleaning a boat fuel tank. Follow these safety precautions to protect yourself and prevent accidents:

• Work in a well-ventilated area : Perform the cleaning process in an open space to avoid inhaling fumes or gases emitted during cleaning.
• Turn off all ignition sources : Before starting, make sure all sources of ignition, such as engines, are turned off to prevent any fire hazards.
• Wear appropriate protective gear : Put on safety goggles and gloves to shield yourself from chemicals and debris while handling the tank.
• Handle fuel with care : Fuel is highly flammable; handle it cautiously, following proper storage and disposal guidelines.
• Avoid smoking or open flames : Keep cigarettes, lighters, or any other potential fire sources away from the cleaning area.

By preparing with the right tools and adhering to safety measures, you can ensure a smooth and secure boat fuel tank cleaning process without compromising your well-being or that of others around you.

Step-by-Step Guide on How to Clean a Boat Fuel Tank

Draining the fuel tank.

To begin cleaning your boat fuel tank, first, you’ll need to drain all the existing fuel from the tank. Locate the fuel line and disconnect it carefully. Position a container underneath to catch the fuel as it drains out. Remember, safety is crucial; ensure there are no open flames or sources of ignition nearby during this process.

Cleaning and Rinsing the Interior

Once the tank is drained, it’s time to clean and rinse the interior thoroughly. Use a mixture of warm water and mild detergent to scrub away any sediment or dirt buildup inside the tank. Consider using a long-handled brush to reach all areas effectively. After scrubbing, rinse the tank multiple times with clean water until no soap residue remains.

Inspecting and Replacing Components

After cleaning, inspect all components of the fuel tank for any signs of damage or wear. Check for corrosion, leaks, or loose fittings that may need replacement or repair. It’s essential to maintain these components in good condition to ensure optimal performance and safety while out on the water.

By following these steps diligently – draining the fuel tank safely, cleaning and rinsing thoroughly, and inspecting for any necessary replacements – you can maintain a clean boat fuel tank that promotes efficient engine operation and enhances your overall boating experience.

Maintaining Your Fuel Tank Post-Cleaning

Regular Maintenance Tips

After cleaning your boat fuel tank, it’s crucial to establish a routine maintenance schedule to keep it in optimal condition. Here are some practical tips to help you maintain your fuel tank effectively:

• Inspect Regularly : Make it a habit to visually inspect your fuel tank for any signs of contamination or residue buildup. Catching issues early can prevent them from escalating into more significant problems.
• Monitor Fuel Quality : Ensure you use high-quality fuel and additives to prevent sediment accumulation in the tank. Contaminated fuel can lead to clogs and engine malfunctions.
• Check Seals and Connections : Periodically check the seals and connections of your fuel tank for any leaks or damage. Addressing these issues promptly can prevent fuel leakage and potential hazards.
• Keep It Full : When storing your boat, try to keep the fuel tank full to minimize condensation formation inside the tank, which can lead to water contamination.
• Use Fuel Stabilizers : Consider using fuel stabilizers during periods of extended storage to maintain the quality of the fuel and protect your engine from harmful deposits.

When to Seek Professional Help

While regular maintenance tasks can be handled by most boat owners, there are instances where professional assistance may be necessary. Here’s when you should consider seeking help:

• Complex Issues : If you encounter complex issues during inspection or maintenance that require specialized knowledge or tools, it’s best to consult with a professional marine mechanic.
• Persistent Problems : If you notice persistent problems such as recurring contaminants in the fuel despite cleaning efforts, a professional assessment may be needed to identify underlying causes.
• Fuel System Repairs : For repairs involving the intricate components of the fuel system like pumps or filters, entrusting the job to an experienced technician is advisable.
• Safety Concerns : Any concerns related to safety, such as suspected leaks or compromised integrity of the tank, should prompt immediate consultation with a professional for expert evaluation and resolution.

By following these maintenance tips and knowing when professional help is warranted, you can ensure that your boat’s fuel tank remains clean and functional, allowing for smooth sailing experiences on the waterways while prioritizing safety at all times.

Maintaining a clean fuel tank in your boat is essential for smooth sailing and avoiding engine troubles. Understanding the importance of this task, recognizing signs of a dirty tank, and taking necessary precautions can save you from potential headaches on the water. By following the step-by-step cleaning guide provided and implementing post-cleaning maintenance tips, you’ll keep your fuel system in top shape. Remember to stay proactive with regular inspections, monitoring fuel quality, and addressing any issues promptly. When facing complex problems or safety concerns, seek professional assistance to ensure your boat’s optimal performance. With proper care and attention to your fuel tank, you’ll enjoy hassle-free boating adventures for years to come.

Frequently Asked Questions

Why is it important to maintain a clean fuel tank in boats.

Regularly cleaning the fuel tank in boats is crucial to prevent engine issues while on the water. Dirty tanks can lead to clogged filters, fuel line blockages, and engine stalling, affecting the boat’s performance and safety.

What are common signs of a dirty fuel tank?

Common signs of a dirty fuel tank include engine sputtering, reduced power output, frequent filter replacements, foul odors from exhaust fumes, and visible debris or contaminants in the fuel system.

What are the potential consequences of neglecting fuel tank maintenance?

Neglecting fuel tank maintenance can result in costly repairs, decreased engine efficiency, increased risk of breakdowns while boating, compromised safety on the water, and potential environmental damage from fuel leaks.

How do you clean a boat’s fuel tank?

Cleaning a boat’s fuel tank involves draining existing fuel, removing debris and sludge using appropriate cleaning agents or equipment, inspecting for corrosion or damage, flushing with fresh fuel, replacing filters if needed, and refilling with clean gasoline or diesel.

What post-cleaning maintenance tips should be followed?

After cleaning the boat’s fuel tank, it is essential to conduct regular inspections for sediment buildup or contamination, monitor fuel quality for water or impurities regularly check seals and connections for leaks tighten loose fittings keep the tank full when not in use use recommended stabilizers to preserve fuel quality over time.

When should professional help be sought for complex issues related to the boat’s fuel system?

Professional help should be sought if there are persistent problems despite DIY efforts signs of extensive corrosion or damage within the tank suspected leaks in the system need for major repairs such as replacing components concerns about overall safety while operating the boat.

Related Posts

How to clean fuel tank without removing: expert safety tips & diy guide, how to clean crawl space like a pro: tips for maintaining a healthy living environment, how to clean implants: essential tips for maintaining oral health, how to clean composite granite sink: maintenance tips for lasting shine, maintain your chenille couch: expert tips for cleaning and stain removal, how to clean amana dishwasher: step-by-step guide for spotless maintenance, leave a reply cancel reply.

Save my name, email, and website in this browser for the next time I comment.

Important Pages

• Editorial Policy
• Privacy Policy

Popular articles

• How To Get Chocolate Stains Out
• Can You Iron Non-Iron Shirts?
• Does Laundry Detergent Have Ammonia?
• How To Separate Clothes for Laundry?
• How Long Does it Take For Dust To Settle After Vacuuming

Editor's Picks

• Does Steam Cleaning Remove Stains
• How to Get a Stain Out of a Backpack
• Does Lemon Juice Remove Blood Stains?
• Can You Iron a Wet Shirt
• Can You Use a Straightener as an Iron?
• Steam Cleaning
• Car Cleaning
• Bathroom Cleaning
• Robot Vacuums
• Stain Removal

Type above and press Enter to search. Press Esc to cancel.

Fuel Polishing - A Complete DIY Guide

Fuel polishing is especially important for boats, as dirty diesel fuel can be a nightmare for boat owners and cause damage to engines.

Fuel polishing systems remove water, bacteria, fungi, dirt, and sludge from marine diesel and boat fuel tanks. Unlike standard filters and water separators, fuel polishing can remove microscopic contaminants and invisible emulsified water from diesel fuel.

In this article, we'll go over the benefits of fuel polishing systems, how they work, and whether or not you need one on your boat. We'll compare them to standard fuel filters and help you choose between these two common options. We'll also list and explain the parts you need to build your own DIY fuel polishing system.

We compiled information for this article from numerous sources on fuel polishing, diesel quality, and manufacturers of filtration systems for marine and land-based use. We also studied the market to find the latest fuel polishing system prices, technology, and quality.

Table of contents

What is Fuel Polishing?

Fuel polishing is a technical term for a complicated fuel decontamination process. Fuel polishing removes numerous contaminants from fuel that standard automotive-type fuel filters don't. Fuel polishing is especially important for marine applications, as fuel stored above ground is prone to contamination.

Standard fuel filters remove large particles and sediment (I.E., dirt) from gasoline or diesel using a membrane, such as paper or mesh. This works well for underground fuel storage, as fuel at gas stations is drained and replenished frequently. For marine applications, particularly diesel, additional steps must be taken to cleanse fuel of impurities.

What Does Fuel Polishing Do?

Fuel polishing removes large particulates (such as dirt) along with water, bacteria, fine particles, and other organic compounds. Here are the primary contaminants that are removed using fuel polishing.

• Emulsified Water
• Dissolved Water
• Organic films

Fuel polishing is used primarily for diesel fuel, as diesel engines are more sensitive to fuel quality than gasoline engines. This is because diesel engines use compression to ignite fuel (as opposed to a spark plug), so any water or other contaminants can severely damage the high-pressure systems.

A small amount of dirt can clog injectors, and water can cause the engine to self-destruct because it doesn't burn away and can't be compressed. Water is the biggest danger to diesel engines, and it's a common contaminant in marine diesel fuel.

How Fuel Polishing Works

A fuel polishing system is usually connected directly to a diesel tank with two separate lines. The intake line, diesel is drawn into the polisher with a pump, is situated with its opening at the lowest possible point in the tank. This is because scum and contaminants tend to settle at the bottom, where the hose can easily pick them up.

Fuel is pumped into the polisher and then back into the tank from the very opposite top relative to the intake. This prevents polished fuel from being drawn back into the polisher.

Stages of Fuel Polishing

The most basic fuel polishing systems contain a minimum of two cleaning apparatuses, known as 'stages.' The first stage of fuel polishing is usually filtration and free water separation. The second stage utilizes a coalescer, which removes emulsified water, which is essentially dissolved moisture.

Free Water Separation

Free water is liquid water that settles inside a fuel tank. It isn't dissolved into the diesel, and it's easy to remove using a centrifugal water separator. Many boats already have a water separator installed, so this process will be familiar to some. The centrifuge works by spinning the solution and separating fuel and water based on their densities.

Centrifugal separators are also useful for filtering out large particles and sludge, such as some of the build-up caused by diesel bug. However, a centrifugal separator cannot remove all contaminants.

Fuel polishing systems filter fuel at least once, usually before entering the coalescer. These fuel filters use a very fine membrane to separate out all particles of dirt, grime, and other gunk to about 25 microns in size. However, filters and centrifugal water separators can't remove emulsified water or some dissolved contaminants from diesel fuel, which is why a coalescer is necessary after filtration.

A fuel polishing coalescer is essentially an advanced filter. It is capable of separating different chemicals based on molecular weight, and it can remove dissolved and emulsified water and other contaminants from diesel fuel.

Some coalescers utilize electrically charged plates, while others rely on purely mechanical processes. Many fuel polishing coalescers also contain a fine filter to remove any remaining particles that escape the first two stages.

Why is Fuel Polishing Necessary for Boats?

Diesel-powered marine engines are robust and reliable. That said, they're still sensitive to fuel contamination, as bad fuel is one of the most common causes of engine failure at sea. Marine diesel engines are victims of a kind of catch-22, as they require more careful attention to fuel, but their fuel is more likely to be contaminated.

Marine diesel tanks get dirty. Shore-based storage tanks, especially at marinas, are often contaminated due to infrequent use or lack of cleaning. Particulates such as bird droppings and rust are particularly common. A quick fuel sample from a local marina revealed that there was a visible amount of dirt in the fuel, and the presence of dissolved water couldn't be ruled out.

A marine fuel-polishing system removes water and other contaminants from fuel. These systems are compact and reliable and an absolute necessity on marine diesel power plants.

Is a Standard Fuel Filter Enough?

Some factors to consider when choosing between a standard filter and a fuel polishing system are the size of your boat, how far you intend to sail, and the size of your fuel tank.

Generally speaking, a standard fuel filter is not enough for a large diesel-powered boat to operate safely. This is due to the high amount of contaminants found in marine diesel fuel. Having a basic fuel filter is still better than having nothing at all, though a robust fuel polishing setup is always the best bet.

If you don't have room on your boat for a complete fuel polishing setup, make sure to install a fuel and water separator. This will ensure that you won't experience hydro-locking, which is a condition where water prevents a cylinder from compressing, and damage occurs. An in-line fuel and water separator is much cheaper than replacing a bent connecting rod.

What is Diesel Bug?

Diesel bug is a rather horrific-looking bacterial or microbial infection that affects diesel and fuel-containing parts. The condition occurs when water permeates the fuel and allows bacteria or fungus to enter and thrive within it. Diesel bug is especially common in biodiesel and in marine diesel tanks.

Diesel bug causes an enormous amount of sludge to build up in hoses, on engine parts, in and around the fuel tank, and even inside of your injection pump.

Does Fuel Polishing Remove Diesel Bug?

Fuel polishing is the best way to prevent diesel bug from migrating to more sensitive parts of your engine from your fuel tank. If you have the option, it's also best to fill your tanks with polished fuel to prevent diesel bug from infecting your tank and clogging filters.

How Much Does a Fuel Polishing System Cost?

Fuel polishing systems are relatively expensive, and the cost isn't justified on all vessels. The most affordable fuel polishing systems cost anywhere between $1,500 and $3,500. Price usually increases as polishing capacity expands.

The most basic fuel polishing systems at entry-level prices use very basic control systems and may require manual input to start and stop. More expensive fuel polishing systems, which typically cost more than $3,000, come with very advanced and reliable automated controls.

High-end fuel polishers are self-regulating and can keep your fuel tank clean for a long time. High-tech sensors monitor the life of filters, the quality of the fuel in your tank, and how long it'll take to polish the remaining fuel.

Do I Need a Fuel Polishing System?

Do all diesel-powered boats need a fuel polishing system, and are fuel polishing systems available for boats of all sizes? The short answer is no. So how do you know if you need a fuel polishing system?

Generally speaking, fuel polishing systems are most effective for vessels with a large fuel capacity. A 200-gallon tank can be scrubbed using an inexpensive fuel tank cleaning machine, whereas a 2000 gallon tank could benefit from a small fuel polisher.

In most cases, diesel-powered boats less than 40 or 50 feet in length probably don't need a fuel system, though small fuel polishers are available for medium-sized boats. In all other cases, a high-quality fuel filter and a centrifugal water separator are good enough to get the job done, and you'll likely be able to solve any contamination issues some other way.

The one notable exception is with ocean-going vessels, even smaller boats less than fifty feet in length. Boats that travel long distances over the open ocean cannot afford to risk a catastrophic failure due to diesel contamination. A fuel polishing system is a mechanical insurance policy against preventable breakdowns at sea.

Can You Build a Fuel Polishing System?

Yes, it's relatively easy to build your own fuel polishing system if you understand the operational principles and acquire all the right parts. The most important things to consider when building your own fuel polisher are proportioning and safety.

The majority of fuel polisher parts are available stand-alone fuel system add-ons. These include centrifugal separators, filters, electric fuel pumps, and coalescers. When acquired separately, these parts cost significantly less than many complete systems.

You can add your homemade fuel polisher to your existing fuel system as well and keep your fuel water separator and original fuel filter. So if you're going to build your own fuel polisher, it may be a good idea to upgrade the entire filtration system.

Can You Rent a Fuel Polisher?

In most cases, you can't just 'rent' a fuel polisher, though you can utilize the services of a fuel cleaning company. There are dozens of fuel cleaning companies located along the coastal United States that specialize in cleaning marine fuel tanks and purifying diesel fuel.

The length of the process and the cost depends on the amount of fuel you need polished and your location. Hiring a fuel polishing company to purify your fuel is an economical way to rid your tank of sludge, diesel bug, and other undesirable and potentially harmful chemicals.

Related Articles

Daniel Wade

I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

by this author

Most Recent

What Does "Sailing By The Lee" Mean?

October 3, 2023

The Best Sailing Schools And Programs: Reviews & Ratings

September 26, 2023

Important Legal Info

Lifeofsailing.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon. This site also participates in other affiliate programs and is compensated for referring traffic and business to these companies.

Similar Posts

How To Choose The Right Sailing Instructor

August 16, 2023

Cost To Sail Around The World

May 16, 2023

Small Sailboat Sizes: A Complete Guide

October 30, 2022

Popular Posts

Best Liveaboard Catamaran Sailboats

December 28, 2023

Can a Novice Sail Around the World?

Elizabeth O'Malley

June 15, 2022

4 Best Electric Outboard Motors

How Long Did It Take The Vikings To Sail To England?

10 Best Sailboat Brands (And Why)

December 20, 2023

7 Best Places To Liveaboard A Sailboat

Get the best sailing content.

Top Rated Posts

© 2024 Life of Sailing Email: [email protected] Address: 11816 Inwood Rd #3024 Dallas, TX 75244 Disclaimer Privacy Policy

The 6 Best Boat Fuel Tank Cleaning Products

Cleaning a boat fuel tank requires using special marine fuel tank cleaners to help avoid damaging the engine.

These products remove dirt, sludge and other harmful substances from your fuel tank.

The best boat fuel tank cleaning products are:

• Best Overall : Star Tron Gas Tank & Fuel System Cleaner
• Best For Corrosion Prevention : STA-BIL 360 Marine Ethanol Treatment & Fuel Stabilizer
• Best For Fuel Treatment : Star Tron Enzyme Fuel Treatment Concentrate
• Best For Price : Sea Foam SF-16 Motor Treatment
• Best For Increasing MPG : Lucas Oil Fuel Treatment Cleaner
• Best Cleaning Kit : Por 15 Fuel Cleaning & Repair Kit

These cleaning products are some of the best for cleaning a dirty boat fuel tank.

We include products we think are useful for our readers. If you buy through links on this page, we may earn a small commission.

1. Best Overall Boat Fuel Tank Cleaner

The top overall marine fuel tank cleaning product is 64 oz. Star Tron Gas Tank & Fuel System Cleaner by the Star Brite brand.

This cleaner is the best all-round marine fuel tank cleaning product and it makes our list of top overall boat cleaning products .

Star Tron Fuel Tank Cleaner

This is a great cleaning product for many outboard and inboard marine motors.

The benefits of the Star Tron Fuel Tank Cleaner are:

• Removes sludge from the fuel tank : The cleaning agent helps remove dirt and sludge build up on the fuel tank walls
• Prevents fuel contamination : This cleaner helps remove and prevent further fuel contaminants from the boat tank
• Works in both gasoline and diesel engines : This cleaning formula can be used in both gasoline and diesel boat fuel tanks
• Clears clogged up fuel lines : The concentrated formula helps to unclog fuel lines and fuel injectors
• Great value for money : One 64 oz. container treats up to 250-gallon tank

To use Star Tron Fuel Tank Cleaner:

• Add 1 fl oz. for every 4 gallons of gasoline
• Let it sit in the fuel tank for a minimum of 24 hours
• Start motor and use the engine as normal

Star Tron Fuel Tank Cleaner on Amazon →

Star Tron Fuel Tank Cleaner on Walmart →

Summary The Star Tron Fuel Tank Cleaner is a great concentrated cleaning product for removing sludge and dirt from the fuel tank. We rate this as the best overall cleaner.

2. Best Cleaner For Corrosion Prevention

The best fuel tank cleaner for helping prevent corrosion is the 8 oz. STA-BIL 360 Marine Ethanol Treatment and Fuel Stabilizer.

STA-BIL 360 Marine

This cleaning agent is specifically formulated for marine engines and fuel tanks. It can be used in most boat motors from inboard to outboard engines.

The 8 oz. STA-BIL 360 Marine treats up to 80 gallons and 1 oz. treats up to 10 gallons.

The benefits of STA-BIL 360 Marine are:

• Stabilizes Fuel For 1 Year : This cleaning product will help stabilize the fuel and keep it fresh for up to 1 year
• Cleans Out Fuel System : This cleaner will erode dirt, varnish, gum and sludge build-up. This will help free up the fuel lines and fuel systems
• Increases Fuel Efficiency : Removing dirt and sludge means the overall fuel efficiency for the boat is much better
• Helps prevent corrosion of fuel lines and walls : The saltwater removal properties in the cleaning formula help prevent corrosion

To use STA-BIL 360 Marine Ethanol:

• Before filling the fuel tank with fuel, pour the product directly into the fuel tank
• Fill up fuel and let it sit for a few hours
• Start the motor and operate as normal

STA-BIL 360 Marine Ethanol on Amazon →

STA-BIL 360 Marine Ethanol on Walmart →

Summary The STA-BIL 360 Marine Ethanol Treatment is a great product for preventing corrosion in the fuel tank and fuel systems.

3. Best Cleaner For Treating Fuel

The 8 oz. Star Tron Enzyme Fuel Treatment Concentrate by Star Brite is the best fuel treatment for the boat fuel tank.

Star Tron Enzyme Fuel Treatment

This cleaning agent is great value for money. 1 container can treat 128 gallons of fuel.

The benefits of Star Tron Enzyme Fuel Treatment are:

• Removes gum, carbon and varnish : This cleaning product will remove old dirt and sludge from the fuel tank
• Helps with the fuel efficiency and performance : Clearing clogged and dirty fuel tanks improves the overall engine health and performance
• Stabilizes fuel for 2 years : This cleaner will provide protection to the fuel and fuel tank for up to 2 years
• Prevents ethanol problems : The special concentrated treatment helps prevent common ethanol problems with old fuels and dirty fuel tanks

To use Star Tron Enzyme Fuel Treatment:

• Add the product to the fuel tank just before filling it up with fuel
• Let it sit for a few hours
• Start up the engine and use it as normal

Star Tron Enzyme Fuel Treatment on Amazon →

Star Tron Enzyme Fuel Treatment on Walmart →

Summary The Star Tron Enzyme Fuel Treatment will treat and clean most marine fuel tanks and fuel systems.

4. Best Fuel Tank Cleaner For Price

The best fuel tank cleaner for the price is the 16 oz. Sea Foam SF-16. This product is great value for money.

Sea Foam SF-16 Motor Treatment

The Sea Foam SF-16 is the best boat fuel tank cleaning product for the price.

The benefits include:

• Stabilizes the fuel for 2 years : It will keep the fuel stabilized for up to 2 years
• Cleans Fuel Tank & Injectors : This cleaning agent will clear out dirt from the fuel tank and injectors
• Easy to use : Simply add it to a vessel's gas or diesel fuel and let it work.
• Prevents gum and varnish formation : The cleaning agent will help prevent dirt from forming with its formula designed to stop dirt buildup
• It's cheap : Many retailers stock the Sea Foam SF-16 for under $20

To use the Sea Foam SF-16 Cleaner:

• Pour the product into the boat fuel tank adding 1 ounce per gallon of fuel
• Start the motor and use as normal

Sea Foam SF-16 Cleaner on Amazon →

Sea Foam SF-16 Cleaner on Walmart →

Summary The Sea Foam SF-16 Treatment is the best value for money boat fuel tank cleaner. It will remove dirt, mold and clean out entire fuel system.

5. Best Cleaner For Increasing MPG

The top fuel tank cleaner that can be used in marine engines for increasing miles per gallon (mpg) is the 1 gallon Lucas Oil Fuel Treatment.

Boaters looking to increase the fuel efficiency of their boat engines should try this product.

Lucas Oil Fuel Treatment

The Lucas complete fuel tank cleaner is a great product for all-round injector and tank cleaning.

The benefits of Lucas Oil Fuel Treatment are:

• Increase MPG in the engine : This cleaner cleans and removes sludge and dirt buildup. This means a smoother and more efficient running of the engine which helps increase mpg
• Fixes low-quality fuels : This will help fix dirt and sludge in the fuel itself making everything run better.
• Cleans and lubricates the entire fuel system : This cleaner will tackle dirt build-up in the tank, injectors and the fuel lines
• Increases fuel tank & pump life : The special formula helps protect the fuel tank and the fuel pump's life
• Helps fix low sulfur diesel problems : The cleaning agent acts to minimize the harmful effects of low-sulfur diesel fuel
• Great value for money : The 1-gallon container can treat up to 400 gallons of gasoline and diesel fuel

To use the Lucas Oil Fuel Treatment:

• Pour the product into your fuel tank using 2-3 ounces of fuel treatment for every 10 gallons of fuel
• Start the motor and use it as normal

Lucas Oil Fuel Treatment on Amazon →

Lucas Oil Fuel Treatment on Walmart →

Summary The Lucas Oil Fuel Tank Cleaner will help remove dirt build up and improve overall engine health. It will also help improve fuel consumption and efficiency.

6. Best Boat Fuel Tank Cleaning Kit

The best boat fuel tank cleaning kit is the POR 15 kit. This kit comes with a metal prep, fuel tank sealer and cleaner degreaser.

POR 15 Fuel Tank Cleaning & Repair Kit

This kit is great for cleaning and repairing damaged fuel tanks.

The benefits of using the POR 15 Cleaning Kit are:

• Rust prevention : The coating in the product helps protect from future rusting of the fuel tank walls and lines.
• Removes dirt, grease and sludge : This cleaning kit will flush out dirt build-up in the marine fuel tank.
• Industrial strength degreaser : The formula used is extra strong and helps tackle the toughest dirt.
• Resistant to all fuels : This means it can be used in most boat engines.

POR 15 Cleaning Kit on Amazon →

POR 15 Cleaning Kit on Walmart →

Summary POR 15 cleaning and repair kit will help give the boat fuel tank a complete overhaul. It will remove dirt, repair rusty fuel walls and clean the fuel system.

What To Look For In Boat Fuel Tank Cleaning Products

There are a number of things to look for when buying a boat fuel tank cleaning product.

Compatibility

A very important thing to consider when looking for a fuel tank cleaning product is whether the cleaner can be used in your specific fuel tank. Some cleaners are only compatible with gasoline fuel while others may only be compatible with diesel fuel.

The price is another important thing to consider when looking for a boat fuel tank cleaner. Depending on your budget, the price of marine fuel tank cleaners can range from as little as $10 to over $100 for higher-end cleaners.

The use case of the boat fuel tank cleaner is another important thing to consider when looking for a marine fuel tank cleaner. Some cleaners are used for preventing rust or removing dirt while others are great for increasing the MPG.

Now Hiring -->   Call Fueltec   (828) 212-1141

Home » Equipment » Marine Systems

MARINE FUEL POLISHING SYSTEMS

Clean your boat's fuel tank.

Fueltec Systems provides a custom tailored maintenance solution for cleaning diesel, and ethanol blended gasoline fuel tanks:  

• Retail Fuel at Boatyards and Marinas  
• Commercial Boats  
• Recreational Boats  

From microbial contamination in ultra‐low sulfur diesel to Phase Separation in ethanol blended gasoline, fuel storage facilities at boatyards and marinas are charged with finding ways to continually improve upon fuel quality while containing or reducing costs.  

Why Use a Marine Fuel Polishing System?

Emergency boats and standby generator sets running diesel fuel are at a great risk for bacterial contamination as they often go through extended intervals of disuse.   Without proper maintenance, sitting water can become a veritable petri dish in your fuel tank.  

In boats fueled by ethanol blended gasoline, water is present, leading to Phase Separation . When gasoline containing Ethanol comes in contact with water—either liquid or in the form of humidity—the ethanol will absorb some or all of that water. When it reaches a saturation point the ethanol and water will Phase Separate, actually coming out of solution and forming distinct layers on the fuel tank bottom.   The result could lower the octane to a point that the engine will not run; or if the alcohol/water mixture is ingested into the engine, sever damage can occur.  

Use a Fueltec Fuel Polishing System to service your boat’s fuel and clean its fuel tank. 

Fueltec Systems is a resource that offers a unique set of turnkey fuel tank service options and equipment designed to help solve these problems for both the boat owner and retail fueling facility.  

Benefits of Using a Marine Fuel Polishing System for Your Boat

Marina facilities.

Reduced Customer Complaints:  A proactive service program with Fueltec Systems, all but eliminates transferring bad fuel.

Elimination of Down Time: Fuel Storage tanks that are properly cleaned and maintained with Fueltec’s Mobile Systems suffer far less down time then tanks that are only serviced when pumps slow down and water is found on tank bottoms.

Eliminate Expensive Emergency Service Calls: Emergency service calls are sometimes done with vacuum service trucks to remove the tank bottom water. Using vacuum trucks without fuel/water separators can lose as much as 300 to 500 gallons of product along with the water.

Filter Cost Savings:  Using Fueltec’s latest proprietary technology and equipment you can remove the filter clogging moisture and bacteria from fuel storage tanks thereby reducing the need to change dispenser filters by as much as 80%

Fueltec’s Systems clean tanks with no loss of product.

Deisel Boat Owners

Prevent Unexpected Engine Shutdown: A pro‐active fuel tank cleaning program will prevent bad fuel issues.

Prevent Bacteria and Fungus: In diesel fuel tanks colonies of filter clogging bacteria and fungus will grow at the fuel/water interface. The by-product of these colonies is acidic sludge which corrode tanks and engine components.  

No Water Buildup in Fuel Tanks: Engines may be exercised regularly and operate properly and to specification. However inside the fuel tank, out of sight, free and emulsified water is slowly accumulating from condensation, leaky tank openings, and even fuel deliveries with high water content. As the evening temperature falls the water begins to condense out of the fuel and build inside of the tank.  

Prevent Fuel Filter Clogging Microbes: When the fuel/water interface grows high enough to reach the engine’s fuel supply tube—which may be one or more inches above the tank bottom—filter clogging microbes will be drawn into the fuel system and stop the engine.  

Gasoline Boat Owners

All boats, gasoline or diesel accumulate water in their fuel tanks from condensation, leaky tank openings, tank vents, and even fuel deliveries with high water content.  

Eliminate Water in Your Fuel:  Many small boat owners fill their tanks with ethanol blended (E10) gasoline at local gas stations.  

When E10 is blended, 10% ethanol (115 octane) is mixed with a low octane gasoline. This combination will give you the required octane to safely run your engine. However, if there is any water in your fuel tank, the ethanol will combine with the water and leave you with low octane gasoline to operate your engine.  

• Your engine will not run on low octane fuel.  
• You may suffer major engine damage if the water or phase separation enters your engine.  

A pro‐active tank cleaning & fuel polishing program can eliminate these problems.  

How to Clean Your Boat's Fuel and Tank

The first step in fuel polishing: “sample your fuel tank”.

Most fuel contaminants, including water, are heavier than fuel and will settle to the fuel tank bottom if undisturbed. 

Always take a fuel sample and place it in a clear container to actually see the fuel contamination in your tank:  

• Take one sample from the top ¼ of the tank to check for clarity.  
• Take one from the tank bottom to check for water, emulsification, and particulates.  
• Compare the two samples.  

If no contamination is found (which is not likely) take more samples in 60 days or an hour after re-fueling.  

If any water is found, slowly remove it by drawing fluid from the tank bottom at a low flow rate to prevent emulsification with diesel or further phase separation with ethanol blended fuels (E10).  

If particulate contamination is found in the sample, filter the fuel with a one micron filter by drawing fluid from the tank bottom.  

Always compare fuel samples from before and after fuel polishing and tank cleaning.  

Tank cleaning is a relative term. A clean tank should be able to store fuel in a condition that exceeds the engine manufacturers recom-mended ISO 18/16/13 cleanliness target.  

Fuel should be delivered to an engine with less than 100 parts per million of free or emulsified water.  

Always draw fluid from the storage tank bottom when cleaning & de‐watering.

Fueltec's BIO-VAC™ 270 Fuel Polishing System is excellent for Marine Applications

Fueltec’s commercial fuel polishing systems are designed for tough cleaning jobs.

Unlike some systems, Fueltec utilizes a low cost ($6.00) bag type pre-filter to remove heavy sludge, rust, and particulate matter to one micron.  

The fuel pump only sees fuel after it has been filtered.  

A (jet fuel type) micro-glass filter/water separator removes water from fuel down to less than 100 parts per million exceeding the engine manufacturers recommendations.  

An air-operated diaphragm fuel pump is safe for all fuels including diesel, jet fuel, gasoline & E-10. The air-operated system can easily be cleaned and hoses emptied to avoid cross contamination when polishing different fuels.  

On-boat fuel tanks with small diameter access ports like the fuel level sender opening, you can attach a small 3/8” ID suction tube to the Fueltec polisher hose. This will allow you to get to the lowest part of the tank to remove water & debris.  

Fueltec’s variable speed air diaphragm pumps allow you to use small diameter suction tubes without damaging the pump.  

All of Fueltec’s mobile systems have two modes of operation:  

• Filtration with water separation  
• Filtration without water separation  

All of Fueltec’s commercial systems come ready to work right out of the box, including a fuel sampler, hoses, fuel pickup tubes, spare one micron filters and a spare water coalescer/filter; just add a small 10 CFM air compressor and you are ready to go.  

Things you won't need to professionally clean and polish fuel in a gas or diesel tank

• You won’t need high price chemicals or so called catalysts.
• You won’t need magnets to remove rust.  
• The Fueltec system does not require messy back-flushing.  
• This Fueltec system does not require high cost water blocking filters.
• Fueltec’s micro-glass fuel water separators work without help.  
• You will not have to stop the Fueltec system to drain the separated water. Fueltec has a pressurized drain.  
• You will not have to guess if you actually separated water from the fuel. You can see it in Fueltec’s sight tube.  

Cleaning a Small Boat Fuel Tank

Cleaning Large Boat Fuel Tanks

Ready to Clean Your Boat's Fuel Tank to Prevent Unexpected Shutdown?

• Search forums
• Practical Boat Owner's Reader to Reader

How to clean a fuel tank with no inspection hatch?

• Thread starter Cardo
• Start date 4 Aug 2014

Active member

We got caught out in some real rolly stuff the other day, the biggest swell we've encountered so far. Boat was tipping over to some quite extreme angles. First time we've had our LJs on and been clipped on! Unfortunately, even though the swell was huge, there was no wind, so motoring it was. The following day as we were motoring along in far milder stuff, I discovered the engine would start hunting when I revved her up to the higher end of the spectrum. I've experienced this before, so knew it was likely to be fuel starvation. Once we'd arrived at our destination, I changed both fuel filters (CAV and engine). Both looked grim. I then pumped some fuel into a bowl, and the first couple of bowls full were really grubby, with loads of black crud mixed in with the fuel. The rolly stuff from the other day had clearly mixed up the crud from the bottom of the tank and a fair quantity of this had been sucked into the outlet. Everything's working as normal now, but I'm concerned we could once again have issues if we get caught out in some nasty stuff. I'm also not massively keen on replacing fuel filters each time we go through a bumpy patch. So, after that tail of woe, the query, as per the title of this thread, is thus: Our stainless steel fuel tank doesn't have an inspection hatch. Only various "inlets" (filler, return fuel, Eberspacher pickup, breather) on the top and a single outlet on the side approx 5cm from the bottom. How do we get this begger cleaned up?  

Well-known member

Cut an inspection hatch?  

You could remove the heater dip tube which should give you a 25mm hole in which to insert a good sized tube right to the bottom then pump the dirty fuel & crud out and filter it back in after settling, not perfect but should get most of it out if you move the tube around to stir up the crud before and during pumping. Or fit an inspection hatch if access is good, not too onerous a task.  

Davids reply makes sense to me. Perhaps a job for end of season before topping up for winter? Has anyone done this?  

Afraid pmagowan is right - cut a hatch. Ariam has had crud in the tank since we bought her, with the filter blocking even on the "delivery trip" from the Hamble to the Itchen (we coasted onto an empty berth in Ocean Village). We've been dealing with it for a season and a half, but it hasn't got any better. Finally, two weeks ago, having fitted the last spare filter just outside Chichester Harbour (and been forced to buy a volvo-branded one at five times the price), I decided enough was enough and installed a hatch. It took a day to make it and a day to fit it (and clean out the tank) but fingers crossed the problem should be no more. Pete  

Enya said: Davids reply makes sense to me. Perhaps a job for end of season before topping up for winter? Has anyone done this? Click to expand...

I cleaned my 12 gallon s/s tank by removing it from the boat and connecting a hired steam wallpaper stripper to it. I spent 2 days doing it and moved the tank into different positions several times. A lot of black crud came out. I carried on until clear water only came out.  

A couple of questions What exactly is an inspection hatch? It sounds as if it is a see through window but presumably can be opened to clean the tank. My tank is 7 galls I haven't had any problems such as described and I do use Fuel Set. However, I must assume that there is some dirt on bottom even if not much and a clean now and again must be a good idea. I thought about pumping out the diesel through the inlet hole after stirring around perhaps a gall or half a gall at a time. Am I asking for trouble? I do not think it would be easy to take the tank off the boat for routine maintenance.  

Enya said: What exactly is an inspection hatch? It sounds as if it is a see through window but presumably can be opened to clean the tank. Click to expand...

Not sure you would want a see through hatch. It would cloud over pretty quickly and would let light at the fuel which would assist in it going 'off'.  

This is not (or at least is not reported as) a bug infestation but rather general crud, I have removed heater dip tubes and pumped small tanks (< 100l)) out to remove crud on a number of occasions to cure heater issues and with some success, usually on boats coming from still waters to coastal, not ideal as I said earlier but a simple process and worth a shot if it is not bug in which case it will not be of any permanent or ever efficacious effect.  

David2452 said: This is not (or at least is not reported as) a bug infestation but rather general crud, I have removed heater dip tubes and pumped small tanks (< 100l)) out to remove crud on a number of occasions to cure heater issues and with some success, not ideal as I said earlier but a simple process and worth a shot if it is not bug. Click to expand...

pmagowan said: How did 'crud' get into the tank? Click to expand...

Cardo said: We got caught out in some real rolly stuff the other day, the biggest swell we've encountered so far. Boat was tipping over to some quite extreme angles. First time we've had our LJs on and been clipped on! Unfortunately, even though the swell was huge, there was no wind, so motoring it was. The following day as we were motoring along in far milder stuff, I discovered the engine would start hunting when I revved her up to the higher end of the spectrum. I've experienced this before, so knew it was likely to be fuel starvation. Once we'd arrived at our destination, I changed both fuel filters (CAV and engine). Both looked grim. I then pumped some fuel into a bowl, and the first couple of bowls full were really grubby, with loads of black crud mixed in with the fuel. The rolly stuff from the other day had clearly mixed up the crud from the bottom of the tank and a fair quantity of this had been sucked into the outlet. Everything's working as normal now, but I'm concerned we could once again have issues if we get caught out in some nasty stuff. I'm also not massively keen on replacing fuel filters each time we go through a bumpy patch. So, after that tail of woe, the query, as per the title of this thread, is thus: Our stainless steel fuel tank doesn't have an inspection hatch. Only various "inlets" (filler, return fuel, Eberspacher pickup, breather) on the top and a single outlet on the side approx 5cm from the bottom. How do we get this begger cleaned up? Click to expand...

Thanks for all the useful replies. It does sound like an inspection hatch would be the most suitable solution. To be honest, I guess it shouldn't be overly difficult to fit one of those purpose made ones to the top of our 200l tank. However, in the meantime, I might see if I can get the crud out through the hole for the sender (forgot that was also there!), which I think is the biggest existing hole. What would be the best way to pump out the existing diesel/crud?  

Cardo said: What would be the best way to pump out the existing diesel/crud? Click to expand...

Now I get it  

Cardo said: Thanks for all the useful replies. It does sound like an inspection hatch would be the most suitable solution. To be honest, I guess it shouldn't be overly difficult to fit one of those purpose made ones to the top of our 200l tank. However, in the meantime, I might see if I can get the crud out through the hole for the sender (forgot that was also there!), which I think is the biggest existing hole. What would be the best way to pump out the existing diesel/crud? Click to expand...

Chris_Robb said: The set up I used on my Westerly Oceanlord through the filler cap in the cockpit floor was as follows: 1. electric drill on fast speed. 2. One pump such as this: http://www.ebay.co.uk/itm/like/3710...f11=ICEP3.0.0&ff12=67&ff13=80&ff14=108&ff19=0 3. 15 mm coper pipe 4. 2 pieces of clear plastic pipe to connect copper to pump and pump top container. Without disturbing the bottom, using the copper pipe move it round the bottom whilst the pump is running at full speed. This will skavenge the **** - provided its not inches thick (as seen in a 1980's moody). This one had a hatch and we had to scrape it out by hand! I use large water bottles, but it really depends how much **** you are removing. If they are see through containers, you will see the nature of the ****. I do this process once a year to keep the tank spotless. You need to see what is settling off the Bio diesel that we are now having to use in the Med! This is an accident waiting to happen. Click to expand...

Members online

Share this page.

Please verify you are a human

Access to this page has been denied because we believe you are using automation tools to browse the website.

This may happen as a result of the following:

• Javascript is disabled or blocked by an extension (ad blockers for example)
• Your browser does not support cookies

Please make sure that Javascript and cookies are enabled on your browser and that you are not blocking them from loading.

Reference ID: 9668901a-6d93-11ef-b6fd-2027853a24c9

Powered by PerimeterX , Inc.

• Forums New posts Unanswered threads Register Top Posts Email
• What's new New posts New Posts (legacy) Latest activity New media
• Media New media New comments
• Boat Info Downloads Weekly Quiz Topic FAQ 10000boatnames.com
• Classifieds Sell Your Boat Used Gear for Sale
• Parts General Marine Parts Hunter Beneteau Catalina MacGregor Oday
• Help Terms of Use Monday Mail Subscribe Monday Mail Unsubscribe

Cleaning diesel tank?

• Thread starter chrisyse
• Start date Oct 30, 2013
• Forums for All Owners
• Engines and Propulsion

Is it reasonable to remove, inspect and clean the fuel tank on a 24 year old C34? We just bought the boat in the spring, and have no evidence of water in the Racor 500/30 micron and secondary 2micron didn't clog. There's no way to inspect for dirt and I'm wondering if an ounce of prevention is worth the effort regarding the chance my filters will clog when in rough water. Has anyone had dirt build up in the tanks ? If yes, please describe how was the tank cleaned? Thanks Chris  

if there are no problems, then it is a lot of work. You may actually induce cracks or pinhole leaks in removing the tank. IF you can cut access hole(s) in the top, you may be able to clean the tank. Were it me, I would be prepared with a "new" tank, just in case this one gets damaged in the R/R, perhaps not have the tank on hand, but for sure have a supplier who can get you one in a few days. Dirt does build up, but filters and having the intake tube an inch off the floor of the tank, usually prevent dirt/debris from being sucked up and in to the system YMMV, and I am sure others with this specific boat/tank will offer their experiences.  

Richard Bryer

I cut a hole and cleaned the tank on my '83 about 5 years ago. I was amazed- I took out about a gallon and a half of stuff that looked like it had come out of my eaves-trough!. Black muck. If I had known that was in there I would never have taken the boat out in waves higher that 6"! And I had never had a problem. Do it.  

Stu Jackson

Many of our skippers have replaced their tanks. Few put inspection covers on because you have to remove the tank from behind the wooden panel on the port side of the aft cabin anyway, so they used the fuel sender hole instead of adding a new one. Our tank is 26 years old, and, like you, we have no indications of fuel problems, so until we do... I've removed the screws on that panel because our next project will to be replace the fuel hoses, which I feel is more important. Here's a fuel tank link for starters: http://c34.org/bbs/index.php/topic,1576.msg26306.html#msg26306 There are TONS of links with just the info you need, and pictures showing what goes on on your boat. Congratulations on your C34. In addition to this fine website, you may be interested in learning LOTS more about your C34 on our C34 website (I read both that and this one regularly). http://c34.org/bbs/index.php/board,11.0.html Look forward to seeing you there, too.  

You can rent or buy a snake camera (Home Depot) to peek inside thru the sender hole. Only need 1/2 inch diameter. It has LED light on the head. You would want to empty the tank first.  

If the tank is aluminum and it's never been cleaned, you're living on borrowed time. Order and install an access plate. I got mine from Seabuilt, but I'm not sure if they're still around because their website isn't working at the moment. Anyway, water accumulates in fuel, algae lives in the water, and forms a slime layer on the tank interior, secreting an acid that eats aluminum. When we pulled the aluminum fuel tank on our '95 H336 a few years ago and opened it up, the walls were covered with a scaly crud. When I scrapped it off, it revealed hundreds of pinholes that had almost perforated the tank. I had to take it to a welder to have a new bottom welded in. Just do it.  

• This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. By continuing to use this site, you are consenting to our use of cookies. Accept Learn more…