FM Magneto

Thu Jul 07, 2005 9:17 am

I have a Magneto on my Dad's 45 Farmall BN. If I remember right he had trouble with the mag when I was a Kid. I just started getting it back in running shape and noticed it does'nt have a H4 but a FM X438 Which I believe is Fairbanks and Morse Is this so, and what was it originally for.
I am in the process of getting an H4 from Magman. He suggests that it will run better.
Thanks PWL

Thu Jul 07, 2005 10:23 am

Phil, Fairbanks Morse magnetos were built for many applications. Your mag could have been on about any early 4 cylinder engine. I don't know if IH used any of them directly in production or not but I guess it's possible and it certainly would not have been out of the question as an aftermarket replacement for the BN.

Thu Jul 07, 2005 10:45 am

The firing order on this is 180 from original order on cap no 1 is where number 4 is and so on. Has an internal coil I think, no coil wire. All kinds of gears that have to be meshed inside. I think when I put an H4 on it it will simplify things.

Thu Jul 07, 2005 10:53 am

Plug wire position in the cap is determined by how the magneto was installed or mis-installed on the engine.

Re: FM Magneto

Thu Jul 07, 2005 11:14 am

PWL wrote:I have a Magneto on my Dad's 45 Farmall BN. It does'nt have a H4 but a FM X438 Which I believe is Fairbanks and Morse Thanks PWL

I have a Fairbanks-Morse mag on one of My Cubs. It is a [FM X4R11D].

Thu Jul 07, 2005 11:31 am

Hang on to the Fairbanks-Morse mag working or not. They are worth money. Suggest at some point repairing the FM mag and using as a spare. Parts are available.

Complicated - Well it takes a bit of thought to figure out the internal timing - gears - good mental exercise.


Thu Jul 07, 2005 12:02 pm

Are there any good reference materials to time them properly.

Like I say alot of moving parts in there
Would like to put new points and condensers in. But opened it and saw
alot of gearing and wanted to wait. Where would I go to get points and condensors for these.
Thanks Phil

Thu Jul 07, 2005 12:48 pm

Phil, check out this link:

Thu Jul 07, 2005 6:41 pm

Magneto parts can be obtained from your local auto parts store. They will need the information obtained from the side of the mag.