there is also the pre-treatment..
'before' letting it sit.
Stay-bil being a well known one.

----- Original Message -----
From: "Don Hanson" <dhanson928@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, July 24, 2011 8:18 AM
Subject: Bad Gas...gummed up stuff..

>  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..