FYI...

  I just discovered that to dissolve the gummy residue from old gas left in
engines or tanks, MEK works very well indeed.

  I am re-activating a couple of our old dirtbikes...A DRZ Suziki and a
KTM...These were pushed aside without very much thought about 5yrs ago.  The
one has a larger aftermarket desert racing tank that had some gas left in
it.  The fuel shut off was so gummed up that it broke apart trying to free
it up and there was a gummy mess in the bottom of the tank where the gas had
totally dried.    It looked like shoe polish or very hard tree sap.

  I was about to toss out the tank as a Lost Cause, with all that crap
frozen  with no access in the deepest parts.  Then I thought, "Hey, let's
give it one last shot.... just see if one of my more aggressive solvents
around here might  soften this mess up"      I have all kinds of nasty crap
around for boatbuilding and painting, so first thing I grabbed was the
MEK...(Methyl Ethel Ketone) which is a pretty brutal solvent for epoxy
resins....and wow!  Poured a little in there (I had previously tried Dri
Gas, Acetone, alcohol, and lacquer thinner) and it immediately dissolved
those gummy deposits, rendering my tank usable again...One should be careful
with this stuff, it is not nice ...

   I'll be using the MEK to soak out some gummy deposits from the carb,
also, though I did run the gas out of that before I pushed the bikes aside,
so that is not so bad.  If I have to clean my injectors sometime on the
vanagon motor, I think I'll be soaking them in MEK for a bit...

  MEK can be bought (in Oregon) from your local Tru Value hardware or Home
Despot, among other places..