Been doing some revamping on my Farmall BN (John's forklift conversion). I love this machine! I had the alternator rebuilt- 2 blade plut and post Delco Remy(internal voltage regulator). After installing this and running new wiring to replace the old ones with cracking insulation, I started the tractor but it wouldn't shut off. Now I'll admit I screwed up and hooked up a new battery backwards and melted the insulation on the 2 main power wires, thus necessitating the complete rewiring. The terminals were reversed on the new battery and I wasn't paying enough attention. Had the alternator checked at the shop that rebuilt it and they said it was not damaged. I replaced the coil. Still wouldn't shut off. I have an on/off switch on the dash that when turned on, gives power to the starter button. I also have a master battery shut off switch. When I shut off the battery the engine would continue to run. The coil was pulling from the alternator to continue to run. Talking to the Starter/Alternator shop, he suggested installing a diode in the wire that was feeding back to the coil. A diode only lets current flow one way and not the other. He gave me one and I installed it in line with that wire that connected to the coil as he instructed and it worked. So if you ever run into that problem, this is something to keep in mind.