I have a 1978 Wheel Horse 8 speed tractor,Kohler 321 engine. I've been working on restoration, finally got the mower deck finished and installed. Before this, the engine was easy to start and ran well. Yesterday it would not start with ignition key, would not even turn over, so I jumped it with a screwdriver between cylinoid and battery. The engine started and ran about 10 seconds and died. Now I get no spark and the engine won't fire off. I checked the wiring and everything seems to be connected and without damage. I don't have test equipment available so I'm stumped at what went wrong. Any suggestions?