Well, if the key is good then ignition timing should be good as long as the air gap on the ignition modules is correct. The only other timing is valve timing and that shouldn't change as long as you got the timing marks on the cam and crank aligned properly. There is a very slim chance the gear on the crankshaft turned on the crankshaft. That would put it out of valve time. Normally that would create a running issue and would lack power.
You can check valve timing fairly easily by pulling the rocker cover off of one side. Turning the flywheel by hand, bring that sides piston up to TDC on the exhaust stroke. At TDC exhaust, both valves should be slightly open. That's called valve overlap. If you move the flywheel back and forth the rocker arms should do sort of a teeter totter. If you get valve overlap at any point other than TDC exhaust stroke, the valves are out of time. That means that unless the timing marks aren't aligned, the gear on the crankshaft has turned on the crankshaft and you would now need a new crankshaft. If you end up needing to replace the crankshaft it is highly recommended to replace the camshaft also. If not you could end up with a noisy engine at best and at worst, you could end up with a cracked crankshaft gear, which will cause the gear to turn again, and you're pretty much back where you started.
I doubt this is your scenario but if you feel it's a timing issue, valve overlap would be the next thing I would check. I'll take it for granted you are running it with the blower housing on and all the baffles in place?
