magneto

I think the FM J was the more common Mag. Maybe the coil is for the J model. I don't know if they would be different.

Per my parts manual, it depends on the engine number. The common mag reference is FMJ4B3. However, for engine # prior to CE-101 and CE-14610 through CE-15109 there's a reference to a distributor. Since you have a mag, I suspect that you don't care about that! You refer to FMX4B3 which differs from the parts book reference. HTH

Edited by Dave(inMA) - 14 Apr 2010 at 8:27pm

I am quickly venturing outside of my knowledgeable areas, but here goes.  I have a X4B3 on my '49 B.  It is my understanding that the X4B3 is an upgraded FM-J.  So the package may still just refer to it as a FM-J.  I think I remember Steve in NJ saying that the coil was sealed differently, so maybe that may be an issue too.  I can't explain the points.  I do have a FMJ and X4B3 manual on .pdf some where.  I'll see if I can dig them out and update later.

I have the FM section of Neil Yernigan's magneot book scanned, and the FMJ instruction sheets scanned.  I can send them to you if you want to send me an e-mail.

Adam

The "J" series Mag was the most common through the B/C model Tractors. Fairbanks released the "X" series mag to replace the "J". One of the main reasons was the wobbly timing gear when the "J" series lower cover that houses the fiber gear bushing wears out. The "X' is designed with everything on the breaker plate, so as you lift the lower dust cover there is no worry of taking the Mag outta' time. One of the big improvements over the "J" series. Both model Mags utilize the same coil, but the contact sets & lower covers are different from one another. The condenser's are the same. The "X" is actually the better Mag and was the last replacement Mag before the Distributor came on the scene. Being I'm a Fairbanks dealer and rebuilder, I stock quite a bit of service parts for all Fairbanks/Morse model Magneto's...HTH
Steve@B&B

hey steve how much to rebuild this one?