How do you test a magnto coil? I bought a riding mower in pieces. The motor has compression, starter works, but no spark. It is pointless. I took off everything apart and sanded the rust off. Put it back together, nothing. I am not sure if the wiring is hooked it right. I have the motor off and turn it over with an extra battery. Jumping the starter. Is there something else I should check? Is there another reason I would not get spark? My wife thought I was nuts for buying it, so now I have to fix it.