Fuel Tank Cleaning Again

[fng]

Hey all, I am about to undertake the fuel tank gunk problem.
I could take it over to a place that does this kind of service but they want 100 bucks to do it.
I pulled the sending unit and looked down inside and although there wasn't any rust, I do see a kind of maroon varnish on the lower 1/3rd of the tank bottom. It smells like old gas and the drainplug was full of a crusty gunk that chiseled out easily with a small screwdriver.
I wonder if someone used a coating of some sort. If so would it be wise to remove it? My thought is to pour in a couple of gallons of B-12 chem tool and let it soak for a day or two. Maybe add some sheet metal screws and shake 'em around a little.
Also the fuel feed line is just potted in with JB weld but appears to be intact. Should I remove and re-pot it as well? The tube turns slightly with medium pressure.
I know this is a well worn subject but any fresh ideas and input would be greatly appreciated. Thanks.........T

[randyscycle]

Here's what I would do with this:

Sounds like there is some varnish, not sealer if its only on the bottom. If it isn't that really nasty thick stuff, get a gallon of the carburetor soak solvent and pour it in, letting it soak for a day or so. Then get a length of chain. I use chain because its easier to retrieve than a bunch of loose screws, and slosh that around till everything is loosened up. Then wash it out really well with a good soapy hot water wash and dry it with the shop vac set on the blow side. That should get it good and clean.

[fng]

Thanks very much Randy. I will do just that. Great idea about the chain too.

[randyscycle]

Yeah, I've dealt with a lot of filthed up tanks, mostly on bikes, and I found that chain seemed to be the best way to clean and still get it back out easily.

If the tank is really bad, that small "dog-chain" if that is what its called officially, works best. That's the stuff that has the double links and its sort of like barbed wire. Seems to have enough rough edge to scrape the inside of the tank good. The flat link chain like they sell for hanging lights works good too.

[randygar]

Unless your tank is constructed quite differently from mine, the baffle will limit you to small, loose objects, or chemical solutions...

--Randy

[fng]

Yeah I noticed that. but at least 1/2 the tank will be scraped.

[randygar]

I'm thinking that next time I have this one off, I'll stick a big hole saw through the filler neck pipe and punch a hole through the top of the baffle... not much benefit to having the baffle at the very top, and that'll let cleaning things get through a lot easier.

--Randy

[randyscycle]

If I remember correctly, my tank had a pretty sizeable gap at the top corners of the baffle, if you looked up into the corners. Enough to feed a small chain through, although I didn't do that on this particular tank.

I will see if I have any pics of it when I did it.

[ldj1002]

CAUTION with chain. Several of you have mentioned chain and apparently had good luck. Maybe I was snake bit but here is what happened to me. The chain got all tangled and knotted up and became kind like a big ball. It was too big to get out and I for a while thought I wasn't going to get it untangled to get it out. Maybe I put too much in or shook and turned it too much or what ever. Just think about that if you use chain.

CAUTION also on the hole saw. They make sparks and sparks can make a gas tank go BOOM!

[randyscycle]

Actually several short lengths work better than one big one. More to move around in there, and less chance of a big wad-up like you experienced.

Funny, but chain can get knotted worse than rope.......