yth2348 Intek V-twin 445577 While mowing engine started to bog down, then sounded like I hit a rock (but don't think I hit a rock) and then engine died and now will not crank. The starter will spin the flywheel but the flywheel does not engage the crankshaft. I can spin the flywheel clockwise by hand. The oil was down half quart but I doubt that damaged anything. Could it be the flywheel key? Where should I start?