Topic: fuel tank gunk from hell

[uwjberg]

ok - so i picked up a cheap '71 CB500 to fix up. in the fuel tank, there was literally .25-.5" of old varnished gas and funk. after a search, i picked up 'the works' and gave it a shot this weekend. the first flush got rid of quite a bit (left it in for about an hour). there was still a thick covering on the bottom of the tank, so i gave it another go with a new bottle (left it in for 1hr 15 minutes). still stuff in there. long story short, i used four bottles of the works on the tank, and there is still areas on the tank bottom that are covered with sludge. i left the last bottle in for almost 2 hours. i used the trick of putting a bunch of heavy nuts and bolts, drywall screws, etc. in the tank and shook it to break stuff loose. still stuff left.

first: i'm afraid of damaging the tank with any more of this works stuff - it's pretty nasty. should i be concerned? or should i try another bottle fo the stuff?

second: if i shouldn't use any more of the stuff, now what? is there anything else i can do to get this cleaned out?

[Bob Wessner]

Along the thinking of the POR-15, three part kit, first part is a degreaser cleaner, second part is phosphoric acid and the final part is liner. Acid (Works included) is inhibited by grease/varnish deposits. I would try something to cut the grease/varnish first, maybe strong solution of Simple Green, or some sort of marine cleaner which is what is in the POR-15 kit. Then, perhaps a final shot of the Works if necessary. Phosphoric acid is the best route as it leaves a rust inhibiting coating on the metal.

[uwjberg]

that makes sense - i have some marine clean, so maybe i'll give that a shot and see what happens.

[Bob Wessner]

that makes sense - i have some marine clean, so maybe i'll give that a shot and see what happens.

Give it a good rinse with hot water before moving on to the next step. Let us know how it turns out.

[uwjberg]

will do. thanks!