Like MonkeyBoy said, but one note. Some well-made two-stroke ABC engines will have a sticky spot when the piston gets to the top (TDC). It may be nearly impossible to turn the crank though that point by hand if you don't have a prop mounted. This is a good thing, don't be alarmed. Get some fuel in there and a prop on it, and it won't be a problem, and your engine will produce the power it should.