Ok we need more information about this engine make model code,and what are you trying to do to this engine? With what you posted we have no idea what's going on.Welcome aboard:licking:
Does this mower have a blade brake? That would be the first place I would check out. Next I would pull the spark plug and make sure the cylinder isn't full of oil or gas. Does the engine have oil in it? If all these things check out it could be big engine problems and new mower time.