Farmall A Magneto

Phil Eastman · Mar 25, 2012

I recently bought a 1941 Farmall A that has the distributor cap off and some of the parts to the magneto. I haven"t pulled any other parts off to look at the points. The tractor has been sitting in a garage for the last 5 years. I did pull the plugs and squirted MMO into the pistons and used the hand crank to turn it over. I will drain the crankcase and change the oil filter. I have the original owner"s manual and the parts manual. I need to know what my next step should be since I have had little experience with a magneto. I would presume the timing is off so what should I do to get this tractor running? Thanks in advance for your expertise.

El Toro · Mar 26, 2012

Remove No1 sparkplug near the radiator and hold your thumb over the plug hole while a helper slowly cranks the engine until you feel pressure against your thumb. Then drop a long plastic straw on top of the piston then you watch the straw rise while your helper slowly keeps cranking. When the straw quits rising No1 piston
should be at TDC on the compression stroke. Then see where your rotor is pointing if it has one. It should be pointing to your No1 plug tower on the cap. That's at 1 o'clock. If your mag is missing the rotor buy one and then see if it's pointing to the No1 plug tower. If you pull the mag when No1 piston is at TDC THEN DON"T MOVE THE ENGINE until you have the mag installed. You still need the rotor at 1 o'clock before installing the mag. Hal

gene bender · Mar 26, 2012

I f it has a magneto it is not out of time as the only way to get them out of time is to mess them up when they are removed from the tractor. You mite want to clean the points if you dont have any spark cause sitting around for a long time the points can get a little film on them. To check the points remove the mag cover at the second point where it bolts to the main body. Removing the first cover just exposes the gears that drive the rotor and its easy to get those gears out of time so the rotor wont fire at the tower on the cap. I would remove all the plugs and then hook one to the wire and ground and then watch for fire that will tell you even the plug wire is good. Do that with all four wires and plugs and their wires. That will elimenate a bad plug and or wire. You can also check compression at the same time.

Haas · Mar 26, 2012

If you have the original manual, it will tell you how to service the points and how to time the magneto. Make sure you have all the parts in there going by the pictures in the manual. If the magneto impulse trips (makes a clicking noise when you turn the engine with the crank) and it makes a spark and the engine has compression, then the tractor should start and run. Make sure you have good gas and the carburetor is not plugged up. Change the oil in the air cleaner and make sure there are not any mud wasps nests in there.

Phil Eastman · Mar 26, 2012

Thanks for all the advice. I will try everything you suggested. I really appreciate it.

Phil Eastman · Mar 27, 2012

I determined I have spark from the magneto to the distributor. I cleaned the points but no spark out of the distributor. I am looking for the place to check TDC on the flywheel I have not found that. Where is it on this A? I must not have the rotor right in the distributor.

Livin the Dream · Mar 27, 2012

These guys are good, they helped me get my Super A going and helped with my mag issues. I had to time my rotor after I had tried everything else they told me....that was it...it took right off. But if you haven't screwed with anything prior your timeing should be fine.

Farmall A Magneto

Phil Eastman

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El Toro

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gene bender

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Haas

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Phil Eastman

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Phil Eastman

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Livin the Dream

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