Engine...older (low time)25cc Homelite. I have done no mods to the ports or timing. Did eliminate gaskets and used Yamabond. I have to get or make a exhaust for it. I am sure a little bigger carb could be used. Have not tried muffler pressure yet or the perry inline pump that works off crankcase pressure. Lots of options to try yet!!!! The prop is a 16x6 APC. This engine does not seem to be a nasty kickback type. May get a boman piston ring. Capt,n