ACB rotor pinion / distributor gear + moisture

Also, to reassemble the distributor cap to the magneto housing, my owners manual says the “marked” tooth of the rotor pinion must mesh between the two marked teeth of the distributor gear at a point marked “C”. Is the “marked” tooth of the rotor pinion the dog-ear tooth?

My distributor gear actually has one tooth marked “A” and the adjacent tooth marked “C”, so I attempt to get the dog-ear tooth of the rotor pinion to mesh between tooth “A” and tooth “C” of the distributor gear. Is this the correct position? Problem is, as you place the distributor cap onto the magneto housing, you lose sight of the distributor gear and rotor pinion...so I am never quite sure if I have meshed them properly. Does anyone have any to tips to make this process easier for an amateur like me?

I really appreciate your help.

HTH.

Scott ks

You should find (look carefully) that the "A" and "C" marks on the distributor gear are actually BETWEEN two teeth and not ON a tooth. There should be a faint line extending from the letter to the valley between two adjacent teeth. The "A" and "C" locations are there to use depending on rotation of the magneto. For the AC-B you should use the "C" location as your manual says. The "marked" tooth of the pinion is the dog-ear one and should be located between the teeth at "C" and NOT between the "A" and "C" marks.

I haven’t had mine apart in years and have forgotten how I lined 'em up the last time...with care I guess :o).

No particular thoughts on your moisture problem except to make sure there are no cracks in either the distributor cap or the cover. I prefer to use new gaskets in lieu of silicone except where absolutely necessary...but admit that silicone should do the trick.

I have a Fairbanks-Morse manual for the FM-J magneto that has an illustrated parts breakdown and service instructions, including timing to the engine. The markings indicated above are also shown in pictorial in this manual. It is a pdf file of just under 1MB. I would be glad to email you a copy at no cost if you wish. Just let me know.

Rod

Thank you for the great advice, and yes, I would really appreciate that FM mageneto .pdf file.

Chris Cramer