There is on at our field, a 36cc, it is a little hoss! No starter needed to crank it, he usually cranks it on the 2nd or 3rd flip and it seems to scream on the top end. Idles a little high IMO but that is the way the guy has it set up. If I flew smaller planes It would definitely be one of the engines I would consider.

He has an in cowl muffler on it. and it still screams.