I have a honda foreman that has been sitting a few years. It now has a layer of sludge in the tank. It looks like thick engine oil coating the bottom. The tank is plastic.

What would be the best way to clean it out? I've thought paint thinner. But thought I should ask before ruining something.

Clean it with gas. Can you remove the tank? If so, add some gas, put the cap on, and shake it-then drain the contents. If you need a little more abrasive cleaning, add some bb's with the gas and shake it around. I used the bb method to clean out a coolant tank on a motorcycle I used to have-worked like a charm!

I second the suggestion of putting any type of rattle solids in the tank with the solvent of your choise. I cleaned a plastic radiator overflow tank using this method. It was hopelessly crudded up and that is the only method that worked. So I recommend this as well unless you want to replace the tank. I did not think of the bbs Phred suggests here, but I can't think of a better rattle medium.

Heat some water in a tea kettle and pour into the tank after adding a healthy shot of dish soap. Water doesn't need to boil, just good and hot. Let it sit over night. Shake, drain and rinse. Let it dry thoroughly before putting it back on the quad.

quote:

Originally posted by Phred:
If you need a little more abrasive cleaning, add some bb's with the gas and shake it around

I did that once, but I didn't have any BB's so I used crushed gravel from the driveway... worked!

I like the BB's. B12 Chemtool will eat that varnish off very easily and I doubt it would harm the tank if exposed only for a few minutes. Maybe let a soaked rag sit on the bottom side of the tank to see if it effects the plastic first.

See how much a new tank is, they might be cheap enough that it's not worth fooling with. If not.

Drain it, take it off and fill it with 3/4 water and a very strong dose of Dawn dish soap. Shake it....let it sit for half a day, shake it a lot again...….after about 2 days, shake it again, drain it and flush it with freshwater many times and allow it to dry completely. It should be clean. I'd be afraid to use solvents on it.

Not sure how it would affect plastic, but I've softened and removed nasty stuff by soaking it with ATF. You should have seen what it did for an old Packard oil pan that had set for 40 plus years!

Thanks for the help guys. Ill give these a try this weekend.

I did the bb’s on a plastic dirtbike tank. I think I used either kerosene or gas and shook the ever loving shit out of it. It worked well, But you’re gonna get a good workout