Have any of you heard of ethanol causing run on after shutdown? I had a customer call and ask if this was a cause. She said a local shop is telling her to run 93 octane to get away from ethanol. Wouldn't higher octane cause the engine to run hotter and be another cause of run on?

Can't say that I have run across this problem with lawnmower engines, 85 octane is fine for L-head engines, they have pretty low compression ratio's.