What we have here is a Farmall 400, 12v negative ground with pertronix ignition and hot coil, one wire alternator. Started right up today, made it out to the yard and died there after about a minute. I measured the battery and it was down to about 12.6 but still turned the engine over enough to start again. Ran for about 30 seconds and I measured the battery terminals to confirm that it was charging about 14 volts. Same thing, little hiccup and dead. Twice more it did the same thing: started ran and idled well and cut out after 30 seconds. On the final attempt to turn it over, the battery sounded weak so I turned the key back to off but it kept weakly cranking anyhow until it ran down the battery. I went to put a charger on it but the charger wouldn't accept the battery while hooked up to tractor (which this charger always has before). So I popped the battery out and put a spare in, connected the positive terminal but couldn't ground it because the negative terminal would spark and smoke awful on each contact of the grounding strap which to me indicates a short circuit somewhere in the wiring. I did check the fuel supply at the carb and gas runs through the line freely so I don't think it is a matter of fuel delivery. Could my ignition switch have failed and created an open or shorted circuit? Thanks,
Pete
Pete