I recently bought a small sears 900 amp generator from the mid 60s that sat for a looooong time with gas in it. The sludge was just like tar, roofing tar. Ive seen this in old car restoration also.
I use some agitation with a wire brush affixed to a coathanger or strong stick. I used diesel/kerosene so I would not have a very flammable mixture. This was ineffective as I was in a hurry.
Then I called a car buddy. and he said let it sit with alcohol gas in it. AFTER A YEAR THAT LITTLE TANK IS CLEAN. iT TAKES TIME TO DISSOLVE TAR. I changed the etoh fuel and enuf oil to reduce flamability, several times, used scrapers, brush etc about 3 times over the winter months for agitation and exposure of lower layers..
On bike tanks, I plug the holes with duct tape after adding a amoniated cleaner(janitor in drum, pine sol) solution in a large plastic bag for spillage, with a small chain with washers zip tied akong the chain, wrap with strings in a towel, then a sleeping bag to prevent scratches.
. Then I tuck it in the dryer (with the cool cycle, no heat) and spin it for about 10 minutes. Then I flip the tank in the dryer, and spin 10 minutes. I center the tank bundle in the dryer with old pillows.
set in hot sun to dry after rinsing, or flush with alcohol or heet. can just set in front of a fan for circulation during drying. I sometimes slip and old t shirt over tanks when off the bike to prevent scratching. Holes can be cut in areas for access.
old foam makes a nice nest in a cardboard box to prevent falling and denting. I cut up old couch cushions if I can grab them curbside before the roofers get them. Also nice to kneel on while bike wrenching if u do not have a lift.
tom
