Wiring Diagrams

Thu Nov 22, 2012 10:06 pm


I have been fixing up a 1947 cub.. I ordered 2 manuals - a service manual and operators manual.

As I am getting ready to re-wire, I discovered that the wiring diagram in the service manual on page 9-5 is incorrect. This diagram shows the wire from the negative terminal to the distributor ....

This is incorrect... It should be the positive terminal to the distributor. It is like this in the operators manual. I verified this on 2 other farmalls.

Re: Wiring Diagrams

Thu Nov 22, 2012 10:16 pm

Originally a 47 would have had a magneto rather than a distributor. However to get to your question, the 6 volt cubs as well as all other IH, and most other brands too, were POSITIVE ground, so the negative wire would have gone to the distributor. They did not change to negative ground until they went to 12 volt electrical systems.

Re: Wiring Diagrams

Thu Nov 22, 2012 11:05 pm



This would be the proper diagram for that year cub from the factory. As John said, they were ALL positive ground until the conversion to 12 Volt
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Re: Wiring Diagrams

Thu Nov 22, 2012 11:06 pm

G'day :D Whilst you are awaiting your manuals, suggest you read this one : McCormick-Deering Farmall Cub Owner's Manual 5-23-47. Verifying a particular wiring situation on 2 other Farmalls does not mean that they are correct. The page you referenced clearly states a battery ignition - which means a distributor and not a magneto. I think you will find out that as John indicated it is correct especially since it should be a positive ground system.

Positive ground systems are not as familiar to many people less than a certain age or are into restoring pre 67 cars/trucks etc., As you get used to Cubs this will become more understandable.

Image to Farmallcub.com :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of which is the Cub Manual Server. Enjoy!.

Re: Wiring Diagrams

Thu Nov 22, 2012 11:48 pm

If someone put a distributor on your Cub then the positive wire from the coil would go to the distributor if you have positive ground.

Is this the diagram you have? It appears to be for a newer Cub.

Re: Wiring Diagrams

Fri Nov 23, 2012 9:24 pm

I bought both manuals at the same time, indicating that I have a 1947. As I indicated, the wiring is different in both.

Barnyard... Yes, this is the diagram I am refering to. The operators manual has a different diagram.

My cub is a 1947 (serial # 17533) and has a distributor. It is a 6 volt positive ground system.

Another local owner has 2 cubs (1 late 40s, the other mid 50s). Both are positive ground with the plus wire going to the distributor.

Re: Wiring Diagrams

Fri Nov 23, 2012 9:36 pm

A '47 Cub, when built, would have matched the first diagram above. When converted to battery ignition, the coil should have been connected with + connected to the distributor. The second diagram above is for a later 12-volt Cub.

Re: Wiring Diagrams

Fri Nov 23, 2012 11:09 pm

The Battery Ignition Packages for Tractors describes how the Battery Ignition/distributor is installed on an Cub equipped with a Magneto. This should solve the issues. As Jim said, the latter diagram on page 9-5 is for the later 12v tractors not the 6v ones.

Re: Wiring Diagrams

Sat Nov 24, 2012 9:12 pm

Thanks for all the replies... I'll get back to re-wiring Monday