HELP Allis Chalmers

Eddie1234 · Mar 25, 2009

I have a 1949 model B Allis Chalmers with a 6 volt positive ground system. The only way I can get the tractor to start is to run a wire from the negative post on the battery to a black tab on the bottom of the magneto. Is this normal?

Eddie1234 · Mar 25, 2009

forgot to post my email....I can be reached at [email protected] if anyone has any information on this topic.

Thanks

Bob · Mar 25, 2009

NO!

You NEVER make a connection from the battery to a MAGNETO.

Eddie1234 · Mar 25, 2009

Bob,
Thanks for your reply, as you can tell I am new to old tractors. So what you are telling me is the tractor should start without any "hot wire" to the magneto? I guess my next question would be, why is the tractor not starting without the "hot wire" to the magneto. One more question...how to I tell if I infact have a magneto not a distributor?

Rusty wheel · Mar 25, 2009

If the mag is working right, you don't need a battery to start the tractor. The mag should produce it's own spark. Yours isn't doing that. You're using the wire from the battery to the mag to put voltage to the mag. The mag is probably fried. rw

Bob · Mar 25, 2009

Here is a "B" with a magneto (Fairbanks-Morse).

<img src = "http://www.alcestertractorclub.co.uk/sitebuildercontent/sitebuilderpictures/.pond/allis3.jpg.w560h420.jpg">

Does your's look like this?

SOME of these old mags were made to function as distributors by disconnecting their internal coil and installing an automotive-type coil EXTERNALLY.

Do you see an external ignition coil like pictured here:

<img src = "http://www.global-b2b-network.com/direct/dbimage/50010969/Oil_Dipped_Type_Ignition_Coil.jpg">

The photo below shows a Delco upright distributor that was used to convert various brands of tractors to distributor ignition. (Shown on an IH.) Got something like that?

<img src = "https://photos.yesterdaystractors.com/gallery/identify/id10471.jpg">

KEB1 · Mar 25, 2009

Is it really a magneto, or are you confusing a distributor for a magneto. Connecting the engine stop terminal on a magnetor to the hot side of the battery will fry the magneto. If its a distributor, then you're essentially "hot wiring" the tractor, and you have an electrical problem somewhere in the ignition circuit.

Keith

garytomaszewski · Mar 25, 2009

Eddie,
Go to the parts and pieces gallery and search for magnetos, your Allis should have a Fairbanks-Morse FMJ, there is also a picture of a 1948 Lai Case that has a distributor that is the same mounting and style as the distributor ignition conversion for an Allis B.

garytomaszewski · Mar 25, 2009

Bob,
You're really good, someday I'll have to learn about posting pictures, I can tell alot more from pictures than words.

El Toro · Mar 25, 2009

You must have a distributor or a magneto that's been converted to a distributor shown in this pic. Hal
PS: Mags don't require outside battery voltage.

Eddie1234 · Mar 26, 2009

My tractor looks exactly like the top picture...there is no coil.

HELP Allis Chalmers

Eddie1234

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Bob

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Rusty wheel

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