My 280 was dead a couple yrs.The problem was a bit intermittent.Turned out that one of the crankcase cover screws (behind the flywheel and stator had come loose and backed out far enough to get the head clipped off by the flywheel.The chunk of metal would get stuck on the ignition pickup and kill the ignition.Probably not your problem,but it could happen and it was really tough to find.