Close this search box.

Moeller Fuel Tank Problems? – 5 Solutions To Help You Out!

Moeller fuel tank

You bought yourself a Moeller fuel tank for your boat. But soon enough it started running into issues. Now, this got you worried!

So, you’re now wondering how to fix Moeller fuel tank problems?

Now the fuel tank’s plastic can get worn out quite easily. Hence you’ll need a replacement to fix that. There might be a similar issue with the fuel pickup tube. So instead of repairing the rubber one, you need to replace it with a steel one. For water build-up in the tank, you need to drain and dry it completely.

That’s just a short preview. Let’s jump into the details and learn more about the process of fixing these!

Common Problems Of The Moeller Fuel Tank

Your cruiser having issues can be a thing of worry. Moreover, it can also be very dangerous to ride the boat without attending to these problems.

Moreover, these can also affect other components of your boat too. The alternator field can get disconnected as well. So let’s go through the common problems you might face and check out the solutions.

Moeller LPTanks

Problem 1 of 5: Gas Tank Leaks After Long Usage

This is the most common issue that you can face. The plastic on your tank can wear out due to corrosion issues. Moreover, this problem when it starts happening can progress quite fast.

The leakage can happen on the seam of the mold joints, or at the filler cap ends. This can be quite dangerous since the leaking fuel and vapor can lead to accidental sparks. You can also face issues with loss of fuel.


Sadly the only option you have for fixing this is replacing the fuel tank. This is because there’s no best way to repair worn-out plastic. Now the replacement can be a hectic process, so we suggest you contact your dealer.

Problem 2 of 5: Rotten Fuel Pickup Tube

Now the problem that happens with the tube is that it’s made of rubber. Hence if the rubber used is untreated and made of cheap material it gets damaged. That too not slightly, it literally gets eaten out by the gasoline reserved in the fuel tank.


Now to fix these issues, you need to change the fuel pickup line. Since the rubber one isn’t good enough you can use the steel one. This will last much longer and is a much more cost-effective solution.

Problem 3 of 5: Faulty Fuel Sender Unit

The fuel sender unit regulates the flow of the fuel going into the engine. However, the motor here might malfunction due to wear and tear. Thus, the fuel sender unit might not work at all and stop the fuel flow immediately.

Also, a faulty unit has the risk of short-circuiting. That can be disastrous for it being in a fuel tank. Plus, it can create problems for the fuel pump as well.


Replacing the faulty sender unit with a new one is the best option that you can do. The device is crucial for keeping the fuel flow stable and continuous. So it’s better to replace the part with a new one to ensure long-lasting performance.

Problem 4 of 5: Water Buildup In The Tank

Water Buildup In The Moeller Tank 2

This too is quite a common issue with Moeller fuel tanks. That is, condensation can happen due to airtight sealing or a humid controller not working properly. Hence there is a water buildup in the tank that can lead to slow damage. Moreover, this can also cause the engine to seize and damage it.


You can easily rectify this problem using the similar process you use for removing water from fuel tanks. Replacing the airtight seals and humid controlling unit can rectify the buildup problem.

Now to keep this problem from happening again, you need to empty and dry the tank sometimes. Doing these steps will ensure the fuel tank won’t have a water buildup anymore.

Problem 5 of 5: Primer Bulb Collapse

The primer bulb is located in the fuel tank. This ensures that the pump can pump out fuel without any trapping air inside the vacuum. But in the case of the primer bulb collapsing, it means that the mechanism malfunctions.

This collapse can hinder the flow of fuel to the engine. Moreover, this can also cause the bulb to fail and the air pressure to build up inside the line. Therefore in turn it can burst the fuel line as well as the fuel tank itself. Moreover, this can also lead to fuel pump problems as well.


The best option would be to change the primer bulb altogether. Repairing these parts is frankly a waste of time. It’s far better to change the whole primer bulb mechanism. That way the function will go smoothly and longer than repairing the damaged one.

That’s all on how you can fix your moeller fuel tank problems.


Moeller fuel tank problems

Question: Where is the anti-siphon valve on the fuel tank?

Answer: The anti-siphon valve is in the tank’s discharge pipe, downstream from the block valve. This is located just outside the tank shell.

Question: What happens if a fuel tank is not vented?

Answer: Without a vent, an end-user will notice swelling in even the smallest of tanks. The vent acts as a relief valve and exhausts the pressure in the tank. Furthermore, the vent allows air to enter the tank.

Question: How do you check a boat fuel tank vent?

Answer: Find access to the fuel tank fill and vent fittings on top of the fuel tank. Once you get to these hoses, remove the vent hose. You’ll see the fuel tank vent just below the hoses

Why does my boat gas tank swell up?

The gas in your tank expands when the temperature outside increases. This is due to the fact that warmer temperatures cause the molecules in the gas to move faster, resulting in an increase in pressure. The pressure from the expanding gas can cause the tank to swell up like a balloon.

There are a few things you can do to prevent this from happening. First, make sure your tank is properly vented so that the pressure can escape. You can also add a fuel stabilizer to your gas to help prevent vapor buildup. Finally, don’t overfill your tank – only fill it up to about 90% capacity to allow for expansion.

Moeller fuel tank problems

These tanks can deteriorate and become less effective at storing fuel.

One reason for this is that plastic is susceptible to UV damage from the sun. This can cause the material to break down and become brittle, which can lead to cracks and leaks in the tank. Additionally, plastic fuel tanks can be affected by chemicals in the fuel itself, which can eat away at the material and cause it to degrade.

Another factor that can contribute to the deterioration of plastic fuel tanks is temperature changes. extreme cold or heat can cause the material to contract or expand, which can lead to cracks and leaks.

How often should a fuel tank be replaced?

A fuel tank should be replaced when it begins to rust or corrode. This can typically happen after years of exposure to the elements, but it can also happen sooner if the tank is not properly maintained. If you notice any rust or corrosion on your fuel tank, it’s important to have it replaced as soon as possible.

In general, you should expect to replace your fuel tank every 25 years or so. However, if you take good care of your vehicle and its components, you may be able to extend the life of your fuel tank.


That’s all about Moeller fuel tank problems. We’ve tried to explain the common problems you may face using the Moeller fuel tank in your boat. We hope the solutions will help you to have a better boating experience.

This is it, take care!

Related Articles