I use E-10 in all our 4-stroke engines, with no problems whatsoever! Ethanol was originally added to reduce pollution, now it's doing that and carrying the farm economy! I was pretty sure you were wrong, so I googled it, and this is what I found!
Ethanol helps keep engines clean, too. It burns more completely and at a slightly cooler temperature than gasoline. ... Oxygen atoms inside ethanol join forces with oxygen molecules in the air to help ethanol burn more completely. This extra amount of oxygen also helps gasoline burn better when it is blended with ethanol.