On Monday, April 24, 2017 at 4:34:08 PM UTC-4, But I'm still wondering why they designed the
ignition circuit with a ballast resistor. Anybody know?
Thanks,
Eric

The total resistance is the wiring, the ballast resister , and the resistance of the coil primary. If all the resistance was zero, the current would initially be controlled by the inductance of the coil, but would be high and burn the points. Some coil essentially have a built in ballast resistor and do not need or use an external ballast resistor.

When you are starting the engine the voltage is lower. So if you short out the ballast resistor it is closer to how it is when the engine is running. So even with the lower voltage when starting , you get a good spark.

Dan