This is odd and I don't know the answer. Only ethanol has been available in our area for 15 years or more. we have two cars, 5 - 4 stroke small engines and 6 - 2 stroke small engines. I have never had any problem that I could attribute to ethanol with any of them and one is a 60+ year old Wisconsin AKN which often sits for prolonged times. I do not drain, use any kind of stabilizer nor concern myself with shelf life with engines and gas cans sitting from one season to the next. Only time I ever had a problem is when I became concerned after reading horror stories on forums, used some Stabil which I didn't realize the shelf life had expired on (My fault) then I really had a mess, that was 6 - 7 years ago, went back to not using anything. No problem. I also work on small engines and occasionally come across a sticking valve which MAY have resulted from ethanol.
Walt Conner