Brew for cleaning filthy gas tanks

[ERROL STILLINGS]

Wowser Bowser. Castrol Super Clean. Will check at Wal Mart first of all. Have Acetone in the tank now with many screws. But, with cold
temperatures, will try Castrol Super Clean and put the tank in the lower level where it is a little warmer than in the garage. Thank you all for your comments. Also, undiluted ammonia is also on the list.

[gofastgramps]

Castrol no longer makes super clean, the stuff you buy today is not at as good as the original. not even close.

[nj-boatbuilder57]

I’ve read this thread a few times now, an I’m a little unsure: is this tank ‘dirty’ with old fuel that has varnished on? Or are we talking about rust?

(I have a rust issue & am looking for solutions…so I’m not sure if this thread’s suggestions are applicable for my tank)

[jeff-register]

Pool acid, muratic acid if the tank is steel, Be careful & read instructions before opening, it’s nasty but will clean it!

[amuller]

quote NJ-boatbuilder57:

I’ve read this thread a few times now, an I’m a little unsure: is this tank ‘dirty’ with old fuel that has varnished on? Or are we talking about rust?

(I have a rust issue & am looking for solutions…so I’m not sure if this thread’s suggestions are applicable for my tank)

I keep trying to make this point…

Most likely, you have old fuel varnish on top of rust, so you need to go after the varnish first. (Because if the tank was coated with "varnish" first it wouldn’t be rusty….) So I would start with solvent or strong detergent first, for the varnish, then go after the rust with some type of acidic cleaner. You might need nails or stones and agitation. Then, I would coat with POR because the plating will probably be gone from the steel.

[ERROL STILLINGS]

My tank has old fuel varnish – I believe. The smell is horrible. The inside of the tank has a coating more than 1/16th of an inch thruout. I didn’t think there was rust beneath but washing out the grease remover I used initially, the result was a rusty colored liquid. Have since put in acetone with lots of screws. Sounds like Castrol might not be the answer – may resort to undiluted ammonia. The tank is large for an outboard – probably more than a gallon.

[seakaye12]

quote Jeff Register:

Pool acid, muratic acid if the tank is steel, Be careful & read instructions before opening, it’s nasty but will clean it!

Is muriatic acid for rust removal or for varnish/sludge removal or both?

I have a six gallon tank with about an inch of roofing-cement like black sticky gooey sludge in the bottom….so thick and sticky that a length of chain doesn’t even slide around.

Will muriatic acid help that Jeff?

[tkwalker]

All of the above are great suggestions.. Instead of screws I use a small chain to drop into the tank … And shake,shake, shake. Now when dealing with rust I do the previously mentioned but make sure the tank is completely dry to the point when shaking you see Rusty dust coming out of the cap opening. The heaver the chain the more impact you have on the rust. Chain is easily removed with magnet. <‘TK><

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