FarmallH4 magneto Coil Resistance

Mtjohnso

Member
No spark from the magneto on the H. Pulled magneto from the tractor at setting at TDC.
I measured the coil in the magneto on the primary and secondary sides.
Primary measured 0.4 ohms and Secondary 12.6K ohms. Does that sound correct?
The condenser show charging when the meter was connected and then discharge when leads flipped the other direction.
The points looked dark but not burnt. The impulse coupler appeared to be working When I took the impulse coupler apart the spring was intact.
One other question is do the magnets in the armature, for lack of better term, get weak over time? How is that tested and can they be rejuvenated?
I plan to buy new points, condenser, coil cap. Rotor looked good and the distributor cap looked good.
What have run into in the past when you had no spark?
 
Odds are the points are the problem. They need to be shinny and not dark colored. The magnets can lose there charge over time. I have been buying and selling H4 magnetos for 8 years. I have yet to find one that needed the magnets recharged.


If you have an ohm meter you could check your points when they open and close.
 

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