help id this mag please.
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=37916
Printed Date: 06 Oct 2025 at 10:31am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: help id this mag please.
Posted By: Glockhead SWMI
Subject: help id this mag please.
Date Posted: 26 Sep 2011 at 6:46am
it says fairbanks morse type fm 4b. 265719 30 degree impulse angle. this is what I was using on my 35 wc. need parts. thanks |
Replies:
Posted By: waynem
Date Posted: 26 Sep 2011 at 7:00am
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That is the same magneto on my 39 Model B. My serial # is 298166 ------------- 1939 Model B |
Posted By: Jeff Z. NY
Date Posted: 26 Sep 2011 at 7:10am
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Glockhead SWMI, That's a Fairbanks-Morse FM4B.
------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: TomMN
Date Posted: 26 Sep 2011 at 7:46am
|
If you are looking for parts it would be an FMK 4B and there would be a 3 after that number if it was originally shipped to Allis Chalmers, so FMK4B3. Parts are not readily available for that mag like they are for the FMJ or FMX. Some of the rebuilders still have some parts for it though. I was able to get some NOS parts for mine on eBay. I think the coil number for the K is U2477C, the coil for the FMJ can be used in it you just need to center it and tighten it down and then add a couple inches to the wire to make it reach. The rotor is an odd thing too and gets a pit worn in it where the spark happens, it just eats a deep divot into it. If it isn't too deep you can use a surface grinder on it and take the whole face down to where it is smooth and level. Here is a link to when I was rebuilding mine: http://home.comcast.net/%7Eold_allis/ac-RC-magneto.html - http://home.comcast.net/~old_allis/ac-RC-magneto.html You may want to check with Steve at B&B, I got some parts for mine from him. |
Posted By: Jeff Z. NY
Date Posted: 26 Sep 2011 at 7:54am
|
If you want that magneto rebuilt with new parts, remagnetized and painted give Belanger's Auto Electric {Mainely Magnetos} a call.
I had them do several of those and when they come back they are like new and work perfect. 207-834-7309 ------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: Glockhead SWMI
Date Posted: 26 Sep 2011 at 9:01am
| I wonder if this is worth trying to repair or if I should look for another mag. |
Posted By: Jeff Z. NY
Date Posted: 26 Sep 2011 at 9:07am
 ------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: TedBuiskerN.IL.
Date Posted: 26 Sep 2011 at 9:12am
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I have that same mag on a 39 RC, must have been popular that year. ------------- Most problems can be solved with the proper application of high explosives. |
Posted By: arrowcreekfarms
Date Posted: 26 Sep 2011 at 9:29am
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Rebuild it! Mags are expensive and unless you see it work you wont know if it does work. I bought a mag for an off color tractor to replace the bad mag I had, it had spark but a bent shaft done me in and I wouldve been better off rebuilding my mag and the ease of mind knowing it was rebuilt right with a backed warranty and all new guts!
------------- 1972 200 diesel, 1966 190 Gas, 1962 D-15 Gas w/ #15 loader, SC 3-16" Plow, SC 8ft disc, SC 2 Row Cultivators, 500 Series 4 row Planter |
Posted By: Glockhead SWMI
Date Posted: 26 Sep 2011 at 9:40am
| If I can find parts I'll fix it up. looking for a cap and rotors now. found everything else. this mag has spark but it is very weak. hope to fix it and my wc might start easier. thanks |
Posted By: wkpoor
Date Posted: 26 Sep 2011 at 12:54pm
| I'll bet all the parts to fix it up are available new. I bought just about everything needed for a full rebuild of a FMJ and it cost just about 150.00. That didn't include the cap since I think mines OK. They are about 65.00 by themselves. |
Posted By: Greg (Hillsboro, OH)
Date Posted: 26 Sep 2011 at 1:09pm
| Steve at B&B will have everything you need to fix it. |
Posted By: Glockhead SWMI
Date Posted: 26 Sep 2011 at 1:20pm
| I have found most of the items. No cap or rotor yet. The seals,gaskets and bearings seem good. Curious if the magnets were weak if that would cause a problem. do the magnets fail over time? |
Posted By: norm[ind]
Date Posted: 26 Sep 2011 at 7:29pm
| WE HAVE FM MAG PARTS 1-800-254-3116 |
Posted By: Gerald J.
Date Posted: 26 Sep 2011 at 10:59pm
|
Recharging the magnets is something a good magneto shop can do. Gerald J. |