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How to Clean Out a Boat Gas Tank? 6 Quick & Easy Steps

Written by J. Harvey / Fact checked by S. Numbers

How to clean out a boat gas tank

When was the last time you inspected your boat gas tank? Yesterday? Last week? Last month? Last year? You may have wondered how to clean out a boat gas tank because, at some point, I also started asking why I have to do it.

Did you know that your fuel tank plays a crucial role in your boat’s overall condition? Chemicals usually break down into sludge when stored. When this happens, you may face problems with your engine that all boat owners avoid.

Every boat owner wants a memorable boat trip, but unique in a good way. Nobody wants to travel on the water and ends up in a nightmare. Thus, it is essential to maintain your gas tank to avoid inconvenience and significant boat deterioration.

How to Clean a Boat’s Gas Tank: Steps to Take


The bulkhead of the engine room typically houses the fuel oil and diesel oil service tanks. To avoid leakage, low service fuel oil and marine gas oil are stored in different tanks. A gas tank is a secure place to store flammable liquids.

Though any fuel storage tank may be called a gas tank, the earlier term is usually used to refer to a part of an engine system where fuel is stored and injected into an engine (fuel pump) or discharged (pressurized gas).

You can follow many procedures when you search about how to clean out a boat gas tank. Here, I will show you the simplest ways you can perform to achieve a clean gas tank.

Step 1: Fuel Tank Draining

The first thing you need to do when cleaning a fuel tank is to empty a boat’s gas tank. You can do so by using a pump or a regular hose paired with a pail. This is a crucial step to ensure that your tank is entirely clean.

If you find it tiring or hard to remove the fuel tank, this step enables you to clean without the expense of removing it. Now, there are many ways to drain your gas tank, but a suction would be ideal as it prevents you from direct contact with hazardous chemicals.

Step 2: Connecting Lines, Hoses, and Filter Removal

After draining, double-check that you’ve disconnected the cables. This prevents any type of leakage, like solvent leaks and waste oil spills. When all lines are removed, you can now start clearing all the used filters.

Although filters are not changed regularly, replacing them every time you clean your boat tank helps a lot in boat maintenance. Accumulated dust will affect your filter’s performance, which then, later on, will degrade your boat.

Step 3: Fuel Tank Cleaning

Once you’ve completely drained your fuel tank, you can now start removing any dust, rust, or build-ups in it. You can utilize a vacuum or pressure washer when cleaning your boat tank. Ensure that you clean all the tank’s parts, even the hard-to-reach areas.

After that, let it dry naturally before proceeding to the next step. Some boaters use a dryer to speed up the process, but I prefer letting it dry by itself. You can choose any method which you think is better or suitable for you.

Step 4: Gas Tank Hose Reattachment

Before attaching the gas tank hoses, ensure that all lines and filters are also cleaned. Once everything is set, you can start assembling everything, and your boat gas tank is ready to use.

Step 5: Fuel Tank Care

It would be best to use safer and more reliable gasoline as part of routine fuel tank maintenance to keep the tank in good condition. Just be cautious about what you put in the tank.

It is not enough to clean out a fuel tank every month. However, it’s better to use it once a year, preferably when you’re not using it during the winter.

Step 6: Use Eco-Friendly Fuels

It’s a good practice to feed the boat engine with the fuel it needs, whether it’s diesel engine clean fuel or some other gasoline marine engine fuel. This would have several advantages, including better boating efficiency and fuel-system repair.

For more ideas on cleaning a boat gas tank, watch these tutorials made by Sean Blaise.

Fuel Tank Oils and Fuels Disposal When Cleaning


Proper disposal of used items, tools, and equipment is necessary to avoid problems and further damages. Some things are recyclable, while others are considered permanent discards. Thus, make sure that you know the adequate actions for each item.

It’s essential to do this correctly because it can quickly get chaotic. Why? Cleaning gas tanks mean dealing with flammable items, and thus, need delicate care and maintenance. However, if you are unsure of what to do, it would be best to seek professional help.

Best Gas Tank Cleaners

As I’ve mentioned earlier, there are many cleaners for gas tanks available in the market. The problem is not all products can give you outstanding results. Therefore, here are some of the best gas tank cleaners that you can use.

TA-BIL Storage Fuel Stabilizer

A long-term cleaner that almost any boat owner most recommends. This keeps your fuel fresh for two years. It also helps prevent any build-up inside the tank.

Star Tron Enzyme Fuel Treatment

This product helps prevent fuel problems. You can also use it daily or seasonally. As this is a concentrated formula, it gives better results than other products out there.


As a quick brush-up, cleaning out a boat gas tank is not an easy task. However, with the proper techniques and knowledge, you can achieve fresh fuels and clean gas tanks for a long time. Here are some of the easy steps you can follow:

  • Drain your gas tanks.
  • Disconnect all lines.
  • Clean the fuel tank by pump, vacuum, pressure washer, or any reliable cleaner.
  • Reattach the gas tank hoses.

Besides that, you should also start regular gas tank maintenance to avoid heavy gum or varnish build-ups. For best results, ask an expert for cleaning advice. Always remember that a clean gas tank leads to more extended boating adventures and prolonged boat life.

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