I have a Cub 1320 mower with a Kohler CV12.5S engine. When I turn the key to the run position, the fuse blows. If I replace the fuse and turn the key all the way to the start position, the mower will crank and fire and continue to run when the key drops back to the run position... though the fuse blows again. I have eliminated all of the safety switches, lights, etc from the equation, leaving only the alternator, rectifer/regulator, starter, solenoid, ignition switch, coil/magneto, fuse, and battery. Since the fuse doesn't blow in the start position I can assume the problem is in the two circuits that are connected when the key is in the run position... and the B side of the ignition switch is common to both positions, so I assume the problem is in the alternator and/or rectifier. Just wondered if you guys tend to agree, and also ask if there are ways to test the alternator and recifier/regulator for shorts to see which needs to be replaced?