Even though I have a lot of experiance with glow engines, including some with 4 strokes, I recently managed to mount the rocker cover backwards, flipped the prop hard, thought it was kicking back, but instead it was the interferance of the rocker arms against the cover. The engine started on the second flip, then wondered why the rocker cover was loose. Ran good but power was off. Stripped one of the covers screws, broke the rocker cover, and bent the pushrods. Felt like a complete bonehead! So I guess I am in good company.