Need Help With Farmall H4 Magneto

[SuperA]

I've been having trouble starting my Farmall Super A, NO SPARK, Did all the Regular Test, I am familiar with all of them, and still No Spark. Upon Testing the Wires to the Point, Condenser and Coil with a Test Light, I found that the Coil Wire Lean that goes to the Condenser is Reading GROUNDED all the Time. Does this mean my Coil is Shot? It is Tightly in there and no signs of damage but that Wire, when touched by my test light Lights up, GROUNDED! Any Ideas, input would be greatly appreciated.

 

[DJ54]

Is your mag hooked up to a switch, mounted on the steering post, to shut the tractor off..?? Is that wire still connected to the mag..??

The reason I ask is, if the tractor has set out, even though the switch is in the run/on position, I've had the one on my BN short the mag out. Simply unhook the wire if it is hooked up, and see if there is a difference.

Not saying it will work on all of them, but I sprayed WD-40 around the stem on the switch in the run position, then turned it off & on maybe 20 times, and it seemed to work for a while again.

 

[SuperA]

Thanks for the suggestion DJ, unfortunately, the problem is in the coil itself. The Lead Wire From the Coil Going to the Points & Condenser is Shorted out and reading Dead Ground. I believe the winding inside the coil must be bad.

 

[davesl708]

Thanks for the suggestion DJ, unfortunately, the problem is in the coil itself. The Lead Wire From the Coil Going to the Points & Condenser is Shorted out and reading Dead Ground. I believe the winding inside the coil must be bad.

Have you ohm tested the coil with all the wires disconnected. You should get some resistance but zero. If the ohms are infinite then the windings have break in them.

Could a wire be rubbed through causing the ground?

 

[DJ54]

That was going to be my next question, if the wire going to the points may have a worn place in the sheath.

If it is ka-put, not too big of a deal, you can get a new coil for around for 50.00. Just did a quick check but this one was the least expensive: https://www.brillman.com/store/product_detail/international-harvester-h4-f4-magneto-coil-625 Other vendors want $65.

 

[SuperA]

Having Determined that My Magneto Coil was Definitely SHOT... I Decided to do something Different and Bypass the Mag Coil with a Regular External 6 Volt Coil as On a Distributor , I used a Coil which Does NOT Need a Ballast Resistor.
I also Decided to Remove the Condenser from the Mag also and mount it Outside as well for easier future access.
The attached Video Shows My Finished Set Up. It is working Perfectly and the engine is Hand Cranking Very Easily.

Just thought I'd Post this on Here For Others to See How It's Done Total Cost $25 .