Magneto help
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=129182
Printed Date: 01 Sep 2025 at 3:25am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Magneto help
Posted By: Hubnut
Subject: Magneto help
Date Posted: 24 Sep 2016 at 7:30pm
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The mag on the B I'm restoring was working fine when I removed it. I reinstalled it today to try to start the tractor and it wouldn't fire. I pulled the mag and bench tested it. It was doing two things weird. 1.It would fire weakly almost every click (same plug). 2. It would not catch the spring to build resistance. It worked fine when I got the tractor a month ago. I pulled the cover and the fiber disk is missing a tooth. Any ideas? Steve ------------- 1940 B "Lucy" 1941 B w/ Woods L59 "Flavia" 1942 B w/ finish mower "Dick" 1941 C w/ 3-point "Maggie" 1947 C SFW w/ L306 "Trixie" 1972 314H |
Replies:
Posted By: Tcmtech
Date Posted: 24 Sep 2016 at 10:10pm
Unfortunately it sounds like rebuild time!  Fortunately there are still places that sell the majority of the parts that go into those magnetos so rebuilding it is just a matter of doing some internet searching to pin down what parts you need and where to get them.
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Posted By: Matt (Jordan,MN)
Date Posted: 24 Sep 2016 at 11:46pm
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Since the fiber gear is missing a tooth I'm sure the rotor is out of time hence the weak spark. As for the impulse not catching there could be a few things wrong. 1 is that the pawls are getting sticky and not tipping out as they should. 2 the pawls, pawl plate or stop pin is worn so the pawls skip past the stop pin. 3 the impulse spring broke which you would notice as the drive cup will be loose.
Hope this helps you out. Matt
------------- Owner of Matt Scott LLC Specializing in NOS and used Allis Chalmers tractor & implement parts & liturature and Magneto Repair http://www.mattscottllc.com/ |
Posted By: Hubnut
Date Posted: 25 Sep 2016 at 6:15am
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Thanks Matt. I sent you a PM about getting this one rebuilt. I hope you have some time. Steve ------------- 1940 B "Lucy" 1941 B w/ Woods L59 "Flavia" 1942 B w/ finish mower "Dick" 1941 C w/ 3-point "Maggie" 1947 C SFW w/ L306 "Trixie" 1972 314H |
Posted By: nella(Pa)
Date Posted: 25 Sep 2016 at 6:24am
I have a tooth missing on a fiber gear in my B and it works fine. The fiber gear only drives the rotor.
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Hubnut wrote: