Got the motor to start but not run in my 1961 F-85 unless we bypass the yellow-black wire from the key to the coil, we jump from the positive battery terminal to the positive on the coil.We think it is the 1.8Ω resister wire in the wiring harness and that there is a break in it somewhere between the key and the coil. Where in the wiring harness would i find this link? Any feed back would be great.

Thanks,
Chris.

 

Have you checked if you have juice at the switch wire when the Key is turned? If not it could be the switch.... Tedd

 

I just struggled with starting up a 61 Super 88 I'm working on. Found out that the ignition switch is not quite like other GM ones I've worked on. There are 2 "ignition" posts on it. Yellow and black. One feeds the input side of the ignition resistor, so it gives 6 volts to the coil WHILE THE ENGINE IS RUNNING. It has no power out when cranking. The other wire goes either directly to the coil, or to the output side of the resistor, so it provides 12 volts to the coil ONLY during cranking. Most GM cars, if they do this, have a wire coming from the starter to give the coil 12 volts during cranking.
So, I believe the 12 v. source is the black wire, and that's probably OK on your car. Your issue could be the ignition switch not giving power at the yellow wire, a break in the yellow wore somewhere, or the resistor being bad. I dont' know if you have a resistor wire inline, but most older cars have a white ceramic resistor, near the coil, to reduce voltage to the coil. They do go bad easily, so that would be the first place I'd look.