cleaning old gas tanks

grassroots boatersports time.

the boat i picked up free runs awesome now, but off a gas can. i pulled one of the two tanks today, excellent condition physically. however, said boat last on water in 1991, and they did not drain the tanks. 2 cycle outboard = oil in gas, 95% of the gas evaporated leaving a sludgy mess in the bottom... the filler hole is not big nor is the sending unit hole. this boat is a cheap as can be project, have $300 into it and after gas tanks are put back in it is ready to go out on the lake - so i'd rather not go the "just get new tanks" route. cant afford that anyway.

For sludgy goop let a radiator shop boil it out for cheap. For rusty crap fill with a hot water/muriatic acid mix then por-15 it.

How small is the hole? Could you fit the nozzle to a power washer down there?

how about a gallon or so of kerosene to sit and slosh around in there. Not as flammable as gas.. but still just as harsh on sledge deposits

1 quart of acetone and 1 box of 1/4 STAR washers. (you know the external lock washers) Pour in tank swish around let sit 5 or so minutes shake hard and dump out all the goo and rust. flush twice with more acetone then leave it to dry. Some like to use chain but thats a pain and not as good on rust IMO.

44

Hard to get all the star washers out. Use dog chain. The kind that is two links twisted together with the ends sticking out. Just grab one part of the chain and it all comes out. I do think that is the only acceptable use for dog chain IMHO.

yea.. dog chain is not good for anything except for cleaning out stuff like gas tanks. it is not even good for chaining up a dog

mad_machine wrote: yea.. dog chain is not good for anything except for cleaning out stuff like gas tanks. it is not even good for chaining up a dog

Tell me about it, our last dog was a 60# (we think)rot/lab/boxer mix. She had to be on heavy 1" chain, and that had almost worn thru.

I too used chain to clean out gas tanks, I used fresh gas as a solvent though. Little dangerous but its what I had on hand.

In reply to 44Dwarf:

I use steel BBs to clean parts. They'll fit though really tiny holes and are gentle enough that I use them to clean threads on bolts.

ditchdigger wrote: For sludgy goop let a radiator shop boil it out for cheap. For rusty crap fill with a hot water/muriatic acid mix then por-15 it.

A friend used POR 15 on the gas tank in his VW bus - a few months later it was back at the radiator shop getting cleaned again as the coating was coming off. I don't know if it was applicator error or what but I thought I would throw it out there.

Soon as the gov made the 10% alky rule most tank sealers peeled they were not designed for it. Most have been reformulated but i'd bet theres still a few out there with old batch dates.

The stuff i've had the best luck with is from AirCraft Spruce but it's was not CHEAP.