JD Model M Wiring Diagram

Danny in CO · Sep 16, 2016

First off I'm an old gear head but not knowledgeable on John Deere tractors. I'm helping a neighbor with a JD Model M (1950 we think) that was included when he bought his house. It was in pieces. The previous owner was in the process of rebuilding it, but he had several things wrong. We have it mostly back together. There are 4 wires running from the dash area to the right side of the engine that have been cut near the generator. I think 2 of the wires go to the generator and 2 to the coil/distributor. I don't know which. Plus the previous owner has a Petronix EI for it but not in the distributor yet. And no instructions for it! I'm not sure what will be easiest to get it running, the EI or points and condenser. I'm leaning towards point and condenser, but it looks like there is something missing in the distributor. There is no place for the point and condenser to connect to.

Does anyone have a wiring diagram for a Model M (that shows wire colors), specifically the distributor and generator? And maybe a picture of the insides of the distributor with points.

Thanks!

Matt Thomas · Sep 16, 2016

wiring diagram

Danny in CO · Sep 16, 2016

Great, thanks! I believe the Model M was positive ground originally. If we decide to use the EI, do we need to switch it to negative ground?

Matt Thomas · Sep 16, 2016

Don't have a clue but wouldn't be surprised if it has to be switched to neg ground and 12v. Someone much more knowledgeable than I will need to chime in on what all that entails.

James Howell · Sep 16, 2016

"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]Does anyone have a wiring diagram for a Model M (that shows wire colors), specifically the distributor and generator?[/i:654c4848f0][/b:654c4848f0]</font>"

[b:654c4848f0]Matt Thomas[/b:654c4848f0] provided the correct wiring diagram.

Take a look at the larger display of the same diagram below.

The electrical power comes from the battery cable at the starter switch to the ammeter.

Power comes from the ammeter to both the ignition switch and cut-out relay.

Power comes from the ignition switch to the lights and coil.

Power is ?regulated? by the cut-out relay from the generator.

Power comes from the NEGATIVE terminal on the coil to the distributor.

Hope this helps.

John T · Sep 16, 2016

Danny, it was originally Positive ground. If you use a Pertronix it needs to match your ground or you will fry it. Its possible to change the tractor over to Neg ground if that's what Pertronix you have, post back if you need more info

Unless something was removed the points and condenser attach with small screws down into the base plate.

I think I would start out keeping her original with positive ground and points and condenser then go from there if needed.

If its sat a long time I would Polarize the Generator before start up and probably just do it anyway to be safe.

John T

JD Model M Wiring Diagram

Danny in CO

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Matt Thomas

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Danny in CO

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Matt Thomas

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James Howell

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John T

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