Fordson F (1927?)

[Frank L]

IN the process of rebuiding the engine, I am about to mount the "after market" magneto to the engine and do not see any way to "advance or retard" the spark. The mag is a Fairbanks Morse model FM 04A4 which is mounted across the front of the engine on a alum. casting. The mag is mounted rigid to the casting and I do not see anything inside that would allow it to be advanced or retarded. Is there something that I'm missing or is this setup not adjustable? Any thoughts you may have are welcomed. Thanks, FL

 

[HWess]

The advance/retard function is on the timer (distributor).

 

[Frank L]

HWess, The FM mag is driven by a heilical gear off the end of the cam shaft, which is connected to the shaft of the mag thru two couplings that can be adjusted for the proper timing. There is no separate distributer that I can see. FL

 

[HWess]

Oops, I didn't see the aftermarket part of your mag. I was thinking you had the original mag, sorry.

 

[Maine Fordson]

Frank --

I don't have any specific info about the F-M magneto for Fordson F; to the best of my knowledege, though, the only magneto which allows you to advance or retard the timing is the American Bosch.

There were lots of aftermarket magnetos made for the Fordson, i.e., the aforementioned American Bosch, Apollo, Dixie, Eisenmann, Jaeger, Webster, and Wico, to name a few. They all seem to work just fine without advancing or retarding. My '26 F has a Jaeger magneto (I think), and I've never had it off, and never had any trouble with it.

When re-assembling, make sure the magneto is timed correctly, e.g., make sure that the impulse coupler gives a good sharp snap at the top of the compression stroke. The impulse coupler is what allows a tractor to start at cranking speed. It fires an extra hot spark. If you do not hear that snap, your magneto may have a broken impulse coupler. It is possible for a tractor to start with a bad/intermittent impulse coupler, but to do so requires cranking the engine at fairly high RPM.

If you need a few pointers, look around on this site or shoot me an e-mail & I'll send you what I have on the subject from my archives.

-- Maine Fordson

 

[Frank L]

MaineFordson, Thanks for the imput. I believe that there is no impulse coupler on my mag. The couplings are all adjustable, manually-during set-up, which I have done, but thereis no feature that I can see like an "impulse coupler". I have just been given a digital camera and am learning how to use it. Would be great to show you what I have as soon as I learn how to put an image on the "forum".Tks, FL PS also dont know how to E Mail you.

 

[Anonymous-0]

Your magneto may have internal flyweights that advance the spark as speed increases. The impulse is also internal in most cases. It could get sticky from old grease, or it may have a broken spring or "anvil" or stop pin which holds the drive until spring pressure builds up. The magnetos may be made for CW or CCW rotation. Besides the Bosch magnetos, the Lucas magneto used on the E27N also has manual advance. Magnetos that look almost identical could have different internal timing, relative to the outside couplings.