awhile back i posted about my daughters craftsman rider that the starter cannot roll it over after it comes up on tdc. if i roll it over tdc the starter will spin it. I adjusted the valves to spec (maybe a little on the tight side) and was careful to take it past tdc a half of stroke to get past the compression relief mechanism and it still will not get over the hump unless i help it. I also put a shutoff valve in the fuel line in case it was hydraulicing the cylinder and run it out of fuel. still no change. It runs great once i get it started. Is there any way the timing could be off or the decompression mechanism is worn? Help....Fred