Sorry for the messed up first post. The engine will fire every time the magnets hit the coil. The crank shaft turn two revaluations to one of the cam. So if it is 180 off it will not fire on TDC,or compression stroke. When that happens you need to turn the crank one revaluation to line it up. It's the same thing on a car if it is 180 off you take the distribute rout and turn it 180. Next time you have a engine apart take time to look at the what happens and turn it 180 and see. ........... Curt