Allis B Ground Short

Hey Guys,

I've got a 1949 Allis-Chalmers B that has some sort of a short in the ground. It ran fine all summer until one day late fall it just wouldn't kick the starter. Tried jumping to both posts on the battery with no result. So then I just connected negative jumper to the starter switch screw and touched the positive to the back of the starter and it fired up fine (so I know the starter is good).

I've read about the grounding issues that can occur where the starter sides into the housing, so I've wire brushed that area - as well as the screw that keeps the starter in place.

I've bought new switches for both sides of the switchbox, and an ammeter and traced the wires that go out to the generator, battery and magneto. I've also checked from the negative battery post to the starter switch, as well as from the positive (ground) post to the steering wheel post. When I check from ground post of battery to the starter housing (or the screw in the bell housing) I get nothing.

This is a straight up textbook 6V system with generator and magneto. I keep going around and around trying to find out what's wrong... Any ideas of what I might be missing or what is wrong?

THANKS!

Battery cable do go bad over time and you can look at them till your blue in the face and never see where they are bad. I would try replacing them both. Being a 6 volt system use 0 or 00 battery cables not the 2 gauge you use on a car and if that is what you have then that is your problem and you need the big heavy duty cable for 6 volts

The starter ground actually comes from the lock screw. Take it out and clean up the end of the screw and tighten it in good. The slip fit on the starter inserting into the torque tube is not tight enough to get a good ground. If it was all you would have to do is slide a battery cable end on a battery terminal and not tighten it up. The lock screw has a jam nut to lock the screw from turning. It could be holding the screw from bottoming out as tight as needed.

Also check the battery, with 6V, not much room for error. I also take out the starter setscrew, and run it on a wire wheel, and use antisieze compound, on re-assembly. It protects, and conducts.

After reading about the battery cables, I went back again and checked the ground cable with a voltmeter and found it was giving me intermittent readings... So I took off the battery ground cable and wire brush/wheeled both ends until they shine, as well as the positive post on the battery. (I had already done this with the starter setscrew and opening earlier)

After shining up the battery ground cable and post, I reconnected it and everything fired up!

You never think that a little corrosion will lead to so much trouble...

Thank you guys for all the advice - it all helped!

Yep that is why we say Clean Tight and Bright. Does not take much for 6 volts to get lost