I just bought a 1980 Puch Newport ll that had not run and had a half a tank of gas in it for many years.
I flushed the tank with fresh gas several times and only a few flakes of rust were coming out. Then filled it up again and let it sit overnight. Drained it and used a wire bent with with a "U" and proceeded to probe through the petcock area. I was greeted with this black tar like substance each time I removed the wire. As I probe the bottom I can feel a thick sticky stuff in the bottom and walls of the tank. Its the old gas residue I assume. The overnight soaking seemed to loosen it up a lot but still sticky thick in areas while probing.
What can I use to loosen this up quicker? I did buy a large can od carb cleaner but that seems like a slow/expensive way to go spraying the whole thing into the tank and flushing and redoing.
Any Ideas will be greatly appreciated.