Trying to get an Old Allis Tractor Running (with magneto)

RTR

Well-known Member
Had a fellow "neighbor" call the other day and say he just had bought an Allis Chalmers tractor to sit in front of his antique shop. He said the boys that had it painted it up and fixed it up so it looked real nice. He said that they told him it ran good, but it had ran out of gas on them and they couldn't get it started. Apparently they thought it was the magneto so they ordered new points and a new coil and installed them. Still couldn't get it running. The guy said he bought it non-running and got the old parts they replaced too. He called us (we are Farmall guys) wanting to know if we could fix it for him and get it running because he would like to pull the grandkids with it. He said if not, then that was fine that he just wanted for yard art mainly.

Now.....I'm not familiar with the smaller Allis Chalmers tractors but i am sure they are alot like working on a Farmall Cub or Super A?? All I know is that it is a narrow front and has a magneto. He doesn't know what model it is except for 1940s. I'm sure we could fix it but I need a little guidance on an Allis Chalmers.

Anyone have any suggestions, step by step guide on timing, etc. ???
 
Sounds like an AC Model C. The serial number is located on the top of the transmission, next to the shift lever, and should begin with a C if it is indeed a model C. Magneto timing should be identical to my Model B, shown <a href="http://rodnh.byethost12.com/acb/magtiming/magtiming.htm">here</a>
 
(quoted from post at 05:10:52 03/14/14) Is the Impulse Coupling working??

I'm not sure. He is supposed to bring it over this weekend and he doesn't know either. He barely knew it had a magneto. I found out by description over the phone. How would one go about checking that?

He did say it "tries to start". Without seeing for myself, I'm not sure what he means.
 
(quoted from post at 07:16:22 03/14/14) If they ran it out of gas, make sure all the air is
out of the sediment bowl. It won't start if you
don't

Yeah I'm just hoping that wasn't a story they told the guy cause something else is wrong
 
If they pulled the Magneto off to work on it, they may have lost timing when replaced - you may need to retime - if it "tries to start" I would assume its popping at least once. That means its getting spark and some gas

But spark maybe not at correct time - the Mag can be put in with coupling in 2 different positions and each repeats so neglecting adjustment by slight rotation the odds are 3:1 against if you don"t know what you are doing.

Or you may have a fuel tank vacuum problem - it will fire but can"t get gas - make sure bowl is full and open cap slightly to make sure its vented.
 
The Magneto doesn't seem to be working right. It seems like a spring is broken inside or something. Most of the Farmalls we have worked on have the distributors and if they have mags we will tune them up but if the mag needs drastic work, we just put a distributor on and put the mag on the shelf.

Being this is someone elses tractor, he wants it to run and we don't have a distributor for an Allis. He has a Fairbanks Morse magneto. Who can I get to rebuild the magneto?
 
The 'spring broken' in the magneto may be the impulse coupling that you are feeling or hearing when it turns at slow speed. The impulse retards the timing for starting, and when it trips, the speed of it's release causes a lot hotter spark that just the magneto would make at cranking speed. It is normal to hear it 'snap' when trying to start the tractor.

Garry
 
(quoted from post at 01:33:27 03/26/14) The 'spring broken' in the magneto may be the impulse coupling that you are feeling or hearing when it turns at slow speed. The impulse retards the timing for starting, and when it trips, the speed of it's release causes a lot hotter spark that just the magneto would make at cranking speed. It is normal to hear it 'snap' when trying to start the tractor.

Garry

Who and/or where would I have the magneto repaired / rebuilt ?
 
(quoted from post at 02:44:24 03/26/14) Have you checked spark and timing?

we did not at the time he came by with it on the trailer. We took the mag off to check it, and then proceed with spark and timing, but got as far as the mag impulse coulpling not working like it should. I told him I would check on getting it repaired then we could go from there.
 

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