Yep I think a lot of stations and suppliers use 10% ethanol(or other fillers), my problem is that they don't tell you when you aren't purchasing 100% gasoline. Supposedly, the small amount of ethanol won't hurt small rubber seals, o-rings, etc. but I've never bought that line. Without questioning the kid at the counter, how do you know what you're buying? Also, there's an urban myth that you should switch brands of fuel every once in a while, in order to take advantage of different additives. Is there any truth to this? And back to the topic, I guess I'll stick with what the manual says for my Pac, 89.