Aside from it affecting rubber parts, ethanol is only a problem when it sits for a few months. It separates and forms a gel like substance that clogs up carburetors.
Not only that - when sitting, ethanol can separate from the gas and also collects water, which can form rust and (together with bacteria) generate acetic acid that loves to eat carb housings for breakfast.
Since ethanol free gas in banned since 20ish years here in Germany, we (old car guys) buy something called "Labracin" which deals with that problem.
Labracin Not sure if it is available in the US, but I'm sure there is something similar.
I use it religiously sind 20 years now - especially cause my cars are siting over the winter, as long as we got salt on the roads - and never had a ethanol based problem.
Best, Frank
