[SEL] Rotten gas

[Andy Glines]

I have a relatively modern briggs on a garder tiller.  The engine sat to 
long with gas in it and there is now shellac in the carb.  The old gas has 
been drained and new added.  I cleaned the carb sufficient to get the engine 
running.  It actually ran pretty good for awhile.  I shut it down and the 
next day it won't run again.  I can get it to run with by choking it with my 
hand so I know that there is a fuel flow problem.  Is there anything I can 
add to the gas tank that will clean the gummy stuff as it runs?  I thought 
of putting coleman fuel in but I'm not sure what it will do to the engine 
that is working under a load.