In Reply to: Re: Ford 2N Ignition Coil Circuit posted by Tim Daley(MI) on August 11, 2022 at 04:56:32:
Okay, I didn't say I had a 12V coil. (I have not bought anything new). I wired this tractor some years ago after I did a 12V conversion in accordance for a 6V coil that I had already that was "new". I wired it through the cutout, then through the .5 ohm factory resistor, and then put a 2 ohm ceramic resistor inline to the coil 12V feed. The best I can remember, this achieved the 3.5/4.0 Amp maximum at the coil I was needing.
Now, it ran fine for many years until I was laying hay down with my Ford 515 sickle, and it just quit all at once a week ago. I then began checking wiring, amp gauge, resistors, etc. and found no issues. I then proceeded to the coil and distributor, and found a bad coil & timing advance flyweights coming apart in the distributor. You're right, coils can be fine when cold but, when they are energized the winding break can separate and lose everything. I've been an automotive/diesel mechanic for 42 years. Onboard computer diagnostics technician for 27 of those. I just simply could not remember what Ford wanted at the coil concerning maximum amperage.