How to check magneto


Well-known Member
I"ve got a fence row Allis C loosened up and everything looks good. Can not get a spark. Highly suspect the magneto. Points and everthing in it "Looks Good". Is there a simple way to check the mag? Never messed with a mag before.

Well first off do you have a manual for that ,mag??? If you don't send me an e-mail and I'll send you one that I have in my computer. Also tell me which one you have since theres 2 common ones that could be on a C. One way to test one I know of isn't fun but it works. Turn the mag by hand with it off the tractor and hole on to the coil wire that comes out and then goes back into the mag. If it has any spark at all you will feel it. But if it where me I would start by getting the manual. Oh by the way I have 2 parts Cs on hand if you find you need some parts
Hobby farm
pull out the plugs, put one in a plug wire and set the plug on the bare metal case so it is grounded. crank the motor or mag by hand and every 4th click, you should see a spark at the plug. if not, and the point is clean and wires not touching the ground, then replace the condenser and try again.
The way my dad tested; the kid who was in trouble that day got to help dad; "Here hold this wire while I crank."
Points can look good BUT they can have an OXIDE build-up that causes NO CONTACT. Use some 320 to 400 grid sand paper to shine the contacts. After you use the sandpaper use some clean paper, I use POST-IT Notes, to pull between the contacts to clean an grit from the sand paper off. Do both of these cleaning using the spring pressure from the point spring. Also depending on the type of FM mag be sure you have the bug in time with the points.

If you sand/file the points and that fixes the issue then replace the points as they will start to stick on you from bringing it down to bare metal.

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