Fuel Tanks! Ugh!

Well, its almost time to do it! Clean the fuel tanks, least attractive project of this boat.* I'm sure there is no way around it but if anyone has had luck on cleaning their tanks without cutting holes and scraping, PLEASE TELL ME! I am planning on transferring fuel from one tank to the other cutting inspection ports, scraping and then again with the other tank.* Also, any advice on the cleaning and sealing of the tank top would be greatly appreciated.

Why? The tops of the tanks on my Marine trader were rusted so I pulled them out. I had to cut them into pieces and found that they were really clean on the inside. It is a 1977 year boat.

Also, any advice on the cleaning and sealing of the tank top would be greatly appreciated.


Buy don't build the part you need , OTS.

The po of my boat did not run much The first trip I took (1200mi) I clogged a few filters After that I racked up 800hrs never a problem again So if you run your boat you may be ok

I just burned through 310 gallons of really old diesel fuel.
When I started, there was enough junk in the fuel to clog the drain off under the
Racor filter. I first cleaned out the bowl,
Changed the primary filter and doubled the standard
Stratadyne treatment. I then refuled every 50 to 100 gallons
And treated the addtional fuel. After running
the engines so the fuel cycled with the stratadyne in it and
The addtion of fresh fuel, the diesel in the tanks was very clean.
I never had a blocked filter or any other issue. I think the key is
Running the engine long enough so that the fuel can cycle once it has a good treatment added.

Running the engine long enough so that the fuel can cycle once it has a good treatment added.


This WILL clean the fuel, but the tank walls may still have an inch of crud.

When the going gets rough , and the tank partially full , the sloshing , baffles or not, is when the lack of tank maint becomes a problem.

Keeping the fuel clean is nice , but keeping the TANK clean is the requirement.

Your point is taken . If you have a lot of crud build up, the approach I took will not solve the bigger problem. I have looked at ads that offer tank cleaning and fuel polishing without taking the tanks out, have you had any experience with this type of service ? If yes, are they effective and/or cost effective?

If yes, are they effective and/or cost effective?



Mostly the are poor substitutes for cleaning the tank..

The setup they use is usually an aircraft fuel pump with 120V 15A for power.

They do remove the fuel , run it thru 3 filters and shoot the cleaned fuel back at high pressure.

The hope is the fuel churn will mix the fuel and water , and the filters will get it.

The problem is larger tanks have baffles that mean the high pressure never gets to hit most of the tank interior.

Clean fuel, 1/4 clean tank, not a great deal.But better than nothing .

On a newbuild with an owner that demands proper marine tanks , none of this would be required , but few owners get a say in the build , or understand what to ask for.

Most folks that get a second chance , and replace the tanks, simply reinstall a new version of what ever the builder stuck in.

Thanks for the advice, was connecting the filler hoses from the new deck fittings and the inlet broke! Time for new tanks anyway, don't think I'll be cleaning them afterall, so this thread gets to change direction. How about some advice about steel, aluminum or poly fuel cells. Any better than another?

patzfan4eva wrote:
*Any better than another?

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* * * * Click on "search" at the top of the page and type in "Fuel Tanks". There's more info* there than you may want.