I'm not buying that at all. I am not saying you are a liar, but rather premium fuel was scapegoated.I once worked in a plant of one of the big three automakers. They had a mysterious warranty issue of spark plug fouling. They eventually found out that the fuel supplier had run out of regular and substituted premium without telling the auto company since everybody knew that premium was better. The premium gasoline caused the fouling. I use 89 octane in my chainsaw and trimmers, presumably with ethanol, and never have a problem. BUT, I plan my work to run the tank dry within a few days of filling it and do enough work that the purchased fuel in the containers is always used within a month. When the equipment is stored for the season, it is dry.