Wire - a mystery to me! Advice ..

There should be a wire going from the mag to a switch on the dash to ground the mag and stop the engine. You will need to trace the wire from that switch assuming it hasn't been removed to determine which wire you need to connect. Looks like there are plenty of wiring diagrams on the net. Just Google Allis Chalmers C wiring diagram.

If you want to keep it as it came from the factory and the battery cables are still on it, I believe you will find that one cable has a bigger battery connector than the other, because one battery post is larger than the other. So that is the way the battery goes.

  Gary!  You'll find the answer to anything you care to ask on here.

Our resident electrical wizards will chime in here pretty soon and they will guide you.

I have a diagram that might help........but it is for an Alternator, not a Generator, but might get you going in the right direction.

Thanks much Ted!!  

on a distributor you have wire #9 to get power to the   coil/ point.......... on a magneto, you don't have a power wire, the switch grounds out the wire to the mag to STOP motor.

I have a G,  B, C, and CA shop manual on line that you can down load complete with wiring diagrams. http://geraldj.networkiowa.com/Trees/Allis-Chalmers-G-B-C-CA-Service.pdf

Even with just one battery wire the posts are enough different in size to tell the difference. The wire end will fit the correct post flush with the top of the post.

If you can find regulator or cutout and generator numbers Steve (NJ) should be able to identify the voltage. If it is the original three brush generator with a cutout, I is probably designed for 6 volts but will charge an 8 volt battery and maybe a 12 volt battery. Polarity with a generator depends mostly on the ammeter connections and how the generator has been flashed. For sure when you connect a battery be sure to flash the generator (covered in the owner's manual) before you start the engine the first time to make sure the generator builds voltage with the same polarity as the battery. If it is still positive ground the positive post of the ammeter will be going to the battery and the negative post to the ignition switch and generator. If it has been properly converted to negative ground the negative post of the ammeter will be going to the battery and the positive post to the ignition switch and generator. If it has battery ignition for positive ground the positive post on the coil will be going to the points and the negative post to the ignition switch. The opposite for negative ground. If magneto the coil won't be visible to check and isn't affected by the battery polarity. The coil might have an indication of its voltage that should match the battery voltage.

There is little doubt that an alternator takes better care of a battery, but isn't vintage. And little doubt that an alternator would be negative ground though alternators have been made positive ground few have been made positive ground and SAE standards since the 1960s have only allowed negative ground, I think because transistor radios don't survive reversed voltage. Before that the tractor and automotive industries were split on grounding which proved that both worked, just confused customers to some extent. About that same decade SAE removed 6 volts as appropriate in their standard.

A three brush generator will have a wire from the field post connected to extra terminals on the light switch so turning the lights on increases the generator current.

Gerald J.

I did ..  but it makes sense now .     

Thanks so much ..    it is making sense now .   

Thanks Gerald .    

The firing order is 1 2 4 3

Pull the cap and see which one the rotor is pointing to. 

When you have a mag you can look at someone else's and make your wires the same as theirs. On a distributor number one wire can be in any one of the four holes, and the distributor can be positioned in any part of the rotation.  Technically if you want to mess with someone you can make any one of the four on a mag be number one too.