After killing two lawnmowers in six years, I’ve finally started using non-ethanol gas in them. Two stations within a couple of miles of me carry it, about twenty cents more per gallon. Considering it for my cars, I haven’t had any ethanol-related problems but I don’t like the black crusty mold growing around the fuel filler behind the door. Is ethanol biodegradable? Must be, for mold to be feeding off of it.
I learned my lesson years ago on a nearly new edger, it’s been non-ethanol since then and haven’t had a problem.
Went searching and apparently it’s “Whiskey Fungus,” Baudoinia Compniacensis, more typically a problem in towns with large distilleries, it gets all over everything in such places. With 10% ethanol gasoline, it only builds up in areas where ethanol comes into contact, so around fuel fillers, on gas tanks, etcetera.