I checked my manual and it says with the engine running, check with a timing light. The two marks, crankcase and flywheel, should be aligned. With your engine not running, you can still check it. Remove the spark plug, spin the engine with a socket on a drill at the flywheel, check with timing light. I doubt it is a timing problem though. I would put a new plug in and try it. If it still doesn't crank, pour a little gas into the sparkplug hole. If it cranks then its a fuel problem.