Farmall m no spark

Noah Washine · Jun 16, 2022

hello so i have a 41 farmall m that lost spark all of a sudden. i was tedding hay with it and it worked great had no problems, when i went to park it it started running rough when i hit the trottle quick. idled good. i thought it was the carb but im thinking now it might not be that. then i shut the tractor off, went to start it 5 min later it wouldnt start... i checked spark, nothing... i put a new cap on the mag and that didnt work. swapped the condenser for another one i had and that didnt seem to work. i cleaned and re-gapped points that didnt work either.. could it be the coil? i checked spark after i done that and i have very very weak spark. thanks for your help.

centash · Jun 16, 2022

Very likely the coil. Does it start after cooling down for several hours?

Ben

Tony in SD · Jun 16, 2022

Are you sure the condenser you had is good?

Steve@Advance · Jun 16, 2022

Might check the points with an ohm meter just to be sure they are making good contact.

And check the spark quality directly from the coil, could be a bad rotor.

How is the spark killed, through the switch? If so, try disconnecting the wire, possible there is a short to
ground or a bad switch.

Noah Washine · Jun 16, 2022

No it don't start at all.

Noah Washine · Jun 16, 2022

I'm not 100% sure, I ordered a new one so we'll see if that one works.

Noah Washine · Jun 16, 2022

I put a new rotor on it not to long ago. And I did try disconnecting the wire from the kill switch that don't work.

Charlie M · Jun 16, 2022

Are you dealing with a magneto or a battery ignition. Based on your working sounds like a mag.

wore out · Jun 16, 2022

If you DO decide to replace the coil, it will likely be stuck tight on the coil core.

Be VERY careful removing it, carefully cut off the old coil rather than getting rough trying to force the core out of the coil.

Although it looks like a solid steel rod it is actually made up of laminations riveted together and then ground to a smooth finish.

Here's what happens if you get rough, and the cores are nla unless you can find a good used one.

Noah Washine · Jun 16, 2022

yeah it's a mag. In the future I'm gonna change it over to battery.

Noah Washine · Jun 16, 2022

oh ok thats very interesting, I didn't know it was that challenging to remove the coil. So where is that that rod type thing then ? Is the coil rapped around that?

John M · Jun 16, 2022

Sounds more like a fuel problem than electrical to me. Did you check your fuel flow, or just start swapping parts?

wore out · Jun 17, 2022

(quoted from post at 12:14:38 06/16/22) oh ok thats very interesting, I didn't know it was that challenging to remove the coil. So where is that that rod type thing then ? Is the coil rapped around that?

A new coil will slide right in place on a cleaned up core.

The issue is that engine heat and lots of years can stick the old coil very tight to the core.

Noah Washine · Jun 17, 2022

hmm maybe I should check that. But I checked spark when It started and there was nothing ?

Farmall m no spark

Noah Washine

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centash

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Tony in SD

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Steve@Advance

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Noah Washine

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Noah Washine

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Noah Washine

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Charlie M

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wore out

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Noah Washine

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Noah Washine

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John M

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wore out

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Noah Washine

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