What's a good way to clean used 6 gal plastic tank?

[EBass]

I bought a used plastic 6 gal tank in hopes to get rid of the surging issue on my 25H Merc. The tank has some rust colored sludge on the bottom. (The rust came from the cap that has a metal hook so the cap isn't lost) How do I clean that out of there?

Thank you!

[goose89]

Depends on how much you like your motor, and how much you've got stuck into the dirty, used tank.

You might be able to take a gallon or two of gas and shake it up and dump it back out into your used oil container. Some mineral spirts might work as well.

If I didn't have much into the tank, and it's truly sludge in the tank, and the motor is one that has been good to me and I didn't want to risk anything, I'd fork over $25 for a new one and forget about it. good luck....

[hawgchaser]

I bought a used snowmobile some years ago that had old gas/sludge in the tank (hadn't been run in 7 or 8 years). I took it off, put a couple pounds of P-rock in it, poured in a half gallon of gas with some carb. cleaner mixed in, let it set for a couple days and shook/sloshed the tank around till it was all loosened, poured everything out, rinsed it, let it dry and it's been running for several years with no issues.

[SpecialK]

My brother found a product that is reusable that eats rust out of tanks. Pretty sure it was eco friendly as well. I'll try to get the name of the stuff for you.

EDIT: Just re-read and you're talking about a plastic tank. Honestly I would probably just buy a new one. If it was a metal tank, I think the stuff my brother uses is made by Rusteco.

[Ed Carlson]

Run it over to the local mechanics shop and have them flush it with Stanisol...parts cleaner. Might need to run a toilet brush inside to dislodge any very thick accumulations if it's really bad.

Any oil sediments and sludge and/or rust should flush on out. Any residual Stanisol will not hurt anything.

Be suspicious of the old tank cap. You may wish to replace it to head off any problems latter. The rust and goop likely came from there. You do not want any small sediments finding there way into the carb or fuel system of the motor. A new cap is cheap in comparison to carb work.

[EBass]

Thank you for the replies. A new plastic tank (needs to be a certain shape/size, Dura-tank model P6A) with quick disconnect runs $60 plus shipping. No one carries that brand around here though. If I clean this tank I'll need to replace the cap for sure. The seal is half gone any ways. I should've bought a new tank from the get go.

[CAMAN]

I would dump some carb cleaner in, clean it up as best you can with a toilet brush and rinse it out with a little fuel. Dump that into a used oil tank. Fill it up with fresh gas and Seafoam, throw an inline fuel filter on and call her good. Just keep an eye on the filter, if it starts to look dirty replace it. Nothing damaging should get through the filter as long as it is of decent quality. Might need to replace the filter the first couple tanks through but eventually most of the lose stuff should be gone and be back to normal.

Edit: keep a filter with you in the boat incase it plugs up faster than expected.