The resistor wire will only let about 9v through. Measure the voltage, and if it is a full 12v, the wire has been changed.

You can add a ballast resistor to a regular wire to do basically the same thing. The ballast lets full 12v thru until it warms up, and then reduces voltage to ~7-9v.

With points and a resistor wire, there is an additional wire from the second terminal on the starter to the coil. This allows a full 12v during startup. (mine is missing this and still starts fine)