VA Kelly

New User
OK- I'm gonna provide the information given to me by my 86 year-old father over the phone: He has a 1950 A-C B, that he had converted to a 12 volt. After 10-15 minutes of running, it would shut down, and not restart for several minutes. Someone told him that the 12 volt conversion was overheating the electrical system,and that he needed to put a resistor in, and that person put one in, and the tractor has not started since.It cranks, but won't turn over. I live 3 hours away from my dad, and I am determined to get this thing running for him while I still have him in my life. I have never worked on a tractor, and I don't even know where the resistor would be put in the electrical system. If anyone could give me any advice on where to start my quest to fix his tractor, it would be greatly appreciated. I have replaced starters, alternators, distributors,etc, on cars and trucks, so I do have a basic understanding of how to identify these parts. Help!!
 
Might try switching the 2 wires around on the resister. I had the same problem with my c farmall and it turned out to be the problem. If not I'd get a test light. Flip the switch on and start from the back and work my way to the front.
 
It depends on what was done during the 12V conversion, and did this problem start right after the conversion.
If it started right after the 12V conversion it would need a resistor if still using the same 6V coil. The resistor would most likely be bolted to one of the coil bracket bolts, it's a white ceramic looking thing. If a 12V coil was installed it may not need a resistor, depends on what 12V coil was installed.
Another cause would be junk in the gas tank slowing the fuel flow. It would run for a time but the carb float bowl would get lower till it stopped. Then after a short time the float bowl would fill and run again. To check, remove the fuel line at the carb and see it fuel flows at a good rate.
 
I would start by checking for spark. You need a good blue white spark at all 4 plug and it has to jump a 1/4 inch gap or more. If you have that then pull the carb drain plug and make sure you get a good steady flow of gas for 3 minutes. Catch the gas to look for dirt/water in it. If you have poor or no spark hot wire it from the battery to the ignition side of the coil and try running it. If it runs then and runs for a long time then the problem is from the coil back to the battery. If it still dies after say the 15 minutes or so check that the coil is not super hot. If hot good chance it needs to be replace and that is a good time to put a true 12 volt coil on that says NO external resister needed and be done with it
 
thanks to all of you for your help. I'm heading back down to my dad's in 2 weeks, and I definitely have a few starting points to work with. Thank you!!!
 
My guess would be that the coil got cooked before the resistor was put on. Probly could maybe get a coil that didn't need the resistor and loose the resistor.
 
My guess is the B has a magneto and the problem has nothing to do with the 12v conversion but it has a carb or gas flow problem.
 
Doc is correct that a 1950 B would have a magneto from the factory, but it could have been changed to distributor.
 
Why would anyone put a resister on if it didn't have an external coil? Then what would you wire it to?
 
From the factory yes, but I have a distributer on my one 1938. Dad put a distributer on his Allis Chalmers C in the mid 1950's. After 60 years it would be hard to tell which it has without seeing it.
 
basically works like he car your talking about. Look at the coil. If it is an old 6 volt, throw it and the resistor away and install a new 12 volt...... Run the tractor and if it dies, check gas flow into the carburetor.
 

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