IH 300 utility wiring

I'm new to the forum and would appreciate any help. I recently obtained a 300 utility which was converted to 12 volt at some point, but I'm not sure everything is connected properly. Does anyone have wiring diagrams for the 12 volt conversion on this tractor or know where I can find one? I'm also interested to see the 6 volt diagram as well to compare and familiarize myself with this tractor. So far, it runs fairly well but ignition switch will not shut off engine, I have to use kill switch. Also, seems to be possible alternator drain as battery can be fully charged and run tractor for half hour or so and it shuts down abruptly like it is out of gas, but turn the key to restart and absolutely nothing. Any ideas?

A good battery will run the ignition on a tractor for multiple DAYS of operation. If the battery is going dead in 30 minutes you have serious issues, including but not limited to:

1. A serious short circuit. This is a fire hazard. Check for hot wires, smoke, the smell of burning plastic.
2. Your battery is in extremely poor shape.

How are you confirming that the battery is dead?

The tractor is definitely not wired correctly. There is no "kill switch" on a factory setup. It is also not charging because of the 30 minute run time issue.

It would probably be a good idea to plan on completely rewiring the tractor and replacing the alternator. Alternators are not expensive. You can use a factory wiring harness to do a 12V conversion so your best bet is to buy a factory style harness from a source like Brillman, Porch Electric, or Agri Services.

Tractors converted to 12 volt alternators need a diode in the wire I believe to the switch but I could be mistaken about which wire. Without one the tractor cannot be shut off by the switch as the alternator continues to feed power to the coil as long as its till turning. There should also be either a coil made for 12 volts or a 6 volt coil with a resistor in the wire to the coil. Resistors will go bad over time and then you have no power to the coil. They are cheap to replace. You shouldn't have much wiring if you have an alternator with an internal regulator. Alternators can be a 1 wire or a 3 wire. One wires have been known to drain batteries but if its charging it wouldn't happen while its running. If the alternator is working it should charge I believe 13.5 - 14.5 volts (maybe a bit more). When you say the tractor quits and then nothing are you saying the tractor won't turn over like a dead battery or just won't restart.I'd suggest looking over what you have and get back to us with more details of what you see. 6 volt wiring knowledge won't do anything for you with a 12 volt alternator unless you are thinking of converting it back to 6 volts. I have a 12 volt generator on my 300U so it has the same components as a 6 volt except its negative ground so all the conections for lights, etc are reversed.

The diagram does not include the lights, but they are simple single wires going to the lamps from the switch lights are grounded by the housings.

The diagram does not include the lights, but they are simple single wires going to the lamps from the switch lights are grounded by the housings. The original starter relay (solenoid) may not have the I terminal, a 12v ford relay from 1960 will. It can assist starting voltage to the coil. The warning loght can be replaced with a 10 watt 10 ohm resistor, or a 4 amp diode with the flow toward the #1 terminal on the alternator. Jim

sounds like either the coil is bad or the Ballast resistor. Though the ballast would just not run when you released the starter switch. Feel the coil as soon as it stops if hot you have found your problem. If choking helps the stopping then you have a fuel problem and need to deal with that.
As for the charging I would solve the other issue first. Then you can check the charging. Check with the battery cable if you have a small spark when it is touched to the post. If so you have a drain. Now with cable connected take the hot wire off the alternator if your spark is gone then you have found the location of your drain.

Thanks for diagram, after comparing wiring on tractor to diagram I found the wires feeding from the alternator were reversed and there is no diode in wire which could be problem with switch not shutting down engine. After switching wires, I checked alternator and it is charging now and battery is holding charge. Is there anything else that may be causing switch to not shut down tractor? Wire on wrong connector at ignition?

Must have light, diode, or resistor in the wire from ignition to #1 terminal. Jim