Need Internal Resistor Coils

She is painted–beautiful dark metallic green. I noticed print on the new coil that states the coil does not have an internal resistor–must use an external resistor. Could you explain that to me? March 17, 2015.

Ferguson tractors use ignition coils that have an internal resistor. NAPA as well as a number of after-market suppliers sell coils that are equipped with internal resistors. To use a coil that does not have an internal resistor you will have to obtain a suitable resistor from the coil supplier and wire it in series with the coil with the wire coming from the ignition switch. If possible I would suggest returning the coil you received and purchasing a coil that has an internal resistor.