'28 JD-D magneto ignition question (problem) !!

Crazy Horse · Sep 19, 2013

Posting here for my friend who is trying to figure out what's happening with a '28 model D he is working on. The magneto he has (Splitdorf) seems to work fine when hand-turning the tractor under impulse for testing. Remote test plugs show both sides will fire a 5/16" gap across a widened electrode with a decent spark. However, when the tractor is started up and running, the #2 right side plug fades to almost nothing for spark, very weak and at times it disappears altogether. Anybody have an idea of what might be happening?

PopinJohn · Sep 19, 2013

One possibility is points gap changing when running due to worn bearings/bushings.
Another is the coil breaking down as it heats when running.

teddy52food · Sep 19, 2013

Copper core wires? Bushing loose? If heat related, they would both get weak.

'28 JD-D magneto ignition question (problem) !!

Crazy Horse

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PopinJohn

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teddy52food

Well-known Member

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