I have a 1963 John Deere 1010 RS. It has a gasoline engine and everything appears to be original other than the electrical system being changed to negative ground. I’m having some issues with the start circuit and I’m hoping someone here can give me some advice to fix the problem and answer a few questions for me.
1. When the ignition switch is in the off position there is 12 volts from the positive terminal to the starter solenoid, up to the voltage regulator, and down to the ignition switch. When I turn the key to the run position voltage is lost all the way back to the positive terminal of the battery. I’ve replaced the ignition switch and was told it’s probably a short in the voltage regulator. Does the position of the ignition switch change potential in the voltage regulator? Could a short in the voltage regulator drain the circuit of voltage, including the start solenoid which precedes the voltage regulator in the circuit? I’m skeptical of the voltage regulator having a short because when I place a jumper cable directly on the starter solenoid I am able to start the tractor using the ignition switch.
2. There’s a wire from the R terminal (bypass) of the starter solenoid to the positive terminal of the coil. Is this bypass wire necessary having an OEM ignition switch with a resistor?
3. I’m contemplating changing it back to positive ground so it matches the original wiring diagram. Are there any benefits to the tractor being negative ground?
I would appreciate any input and advice I can get, thanks.
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