What to clean gas tank sludge *not de rust*

[Lulu7404]

Just flipped through first ten pages of threads and did a search for tank sludge, and nothing. My tank is pretty lined with the same stuff that was in my carbs... basically congealed gas, I guess. Spraying carb cleaner into sender hole will clean it pretty good but that won't get everywhere...
Ideas or successful things to use/do. Will hot soapy water break this stuff down? What if I poured some of the Berryman's carb dip into the tank and sloshed it around for a while? Sea Foam? Simple Green?
If getting this sludge off reveals rust I will follow up with a de rust procedure, but I think this sludge has kept the tank from rusting...
thanks for any tips...

[chuck hahn]

Acetone will cut it loose..and so will products such as dematured alcohol, can spray a few cans of gumout carb cleaner in and slsoh that around also. Whatever you use, test it on the bottom of the tank or something to test the effects on the paint..if the tank has good paint.

[Lulu7404]

Are mineral spirits strong enough, have about a gallon of that from painting projects. If not i can pick up some more carb cleaner and acetone tonight. paint on tank is not great. i am not worried about it, good reason to repaint it. has a few superficial (i hope) rust spots on bottom near seat anyway.
thx

[Nessism]

I'd use carb dip. Fashion some solid caps for the various holes first though. You can dump the excess back into the can you are done. POR-15 also sells a product intended to clean out all the varnish. You might want to check their website for more info.

[Lulu7404]

Thx for another option John. I spent about 15 minutes today swishing around about half a can of gunk carb cleaner I sprayed into tank. Really dark when it came out, but of course I can't see everywhere in tank and the mirror I bought today at autozone was too big to fit into filler hole.
Question for you about diesel fuel. Will it do any harm to petcock, send unit and gas cap seals? They are all off now, but I was trying to figure out what to use to seal up tank with other chemicals and diesel seems like it would not hurt them unless diesel tanks use those items with different seals on them.
tia

[gsryder]

I just flushed mine out, had light surface rust/corrosion threw a hand full (maybe 30) of nuts in the tank and then continued to flush and shake like crazy with white distilled vinegar. Took about 8 gallons to get it absolutely spotless. Then used a extendy magnet thing through the gas gauge sending unit hole to recover all the nuts. Nice thing about the vinegar it doesnt smell to bad and you just dump it down the driveway. All the other stuff works as well but you end up with a couple of gallons of dirty fuel, degreaser, carb cleaner, whatever you have to deal with.

[Lulu7404]

I had planned on trying the vinegar afterwards, but wasn't sure I wouldn't be wasting my time before I got all the sludge and varnish out first. There is only a mild discoloration where I can see into the tank so far, so I am sure the vinegar will do just fine.

[Nessism]

I'm not so keen on suggestions like solvents, since gas is a strong solvent and won't remove the varnish. The carb dip solution seems more viable to me or get some Marine Clean from POR-15... http://www.por15.com/CYCLE-TANK-REPA...ductinfo/CTRK/

Good luck.

[Lulu7404]

Thx again, John. I am pretty sure most the these guys are removing sending unit and petcock before the NUTS treatment. Using pipe plugs and what have you to seal up openings in tank. Think I am gonna see how it looks today after carb cleaner was sloshed through it. Repeat until clean, or try deisel. Flush with water, then try white vinegar for a few hours for slight rust discoloration. Then flush with water. Dry with hair dryer. MMO to follow to coat the tank. Reattach gas cap, sending unit and petcock and put in some gas, so I can test my cleaned and bench synched carbs. Short term goal is just to get it running, not tuned up just yet, as I need the brakes rebuilt, possible new lines, new tires, and temp seat cover. I want it running before I decide on cafe' job or not.

[gsryder]

Hmmmm....yeah I dont have a sending unit in mine and I have a pingle petcock (metal).

Good catch and warning.

[jhicok]

Agree on acetone... pour in a whole pint and let it sit awhile with the tank propped so it sits at close to the same angle as mounted... so the acetone will sit where the gas settled