I have a '47 C with a Fairbanks-Morse magneto that only has spark on two cylinders. I thought this would be a cap or rotor problem so I replaced both the cap and the rotor (not with a new one, but from another running tractor). I still have the same problem. No spark on the same two cylinders. I have checked the plugs and wires on the two problematic cylinders to see if they work, and they do. Does anyone have any recommendations as to what I should check next? Thank you.
Re: C Allis Magneto-Spark on only 2 cylinders in reply to JordanNC, 07-27-2008 14:19:00
The problem could be a very weak magnetic field at the magnetic rotor. If that is the problem, re-magnetizing the rotor assembly is the fix. I've had mags come in for repair that had the problem, when I first ran them on the bench, and after a good rebuild and re-magnetizing the rotor assembly, the fire is back at all four holes with a vengence. Another problem F/M had with its early version Mags is the tar-taped coil that was used. These coils would "leak" to where stray spikes would ground to the inside of the Mag housing and either kill the engine or kill a cylinder or two. HTH Steve@B&B
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