I have a late '80s scag with a Kohler MV18 engine. After hitting a tree branch and stalling the motor, the starter would turn the engine over, but it would not start. I checked the 0.010" air gap disconnected the kill wire from the ignition module and it still would not start. I also checked the resistance of the coils and determined it was bad so I replaced the ignition module and the keyswitch. Upon installation of both items, it started right up. After shutting it off with the keyswitch, it won't start again. I measured the resistance of the ignition module and it appears to have gone bad during that one time running. What would be causing it to go bad and how do I go about beginning to diagnose it? The manual for the engine the ignition module has a diode which protects it from 12V being applied to the kill terminal. Is there any way to fix this ignition module? I have a feeling it was the act of shutting it off with the keyswitch that killed it. I was able to successfully shut it off before by grounding the kill terminal.