How Do You Check Out Tractor Ignition Coils?
Ignition coils supply the distributor with high voltage electricity to fire the spark plugs. The coil consists of a primary winding (coil of copper wire) and a secondary winding inside of the housing and in very close proximity to each other. The primary winding is energized with battery voltage by the ignition module or, in older engines, the points. Coils may be of the rising-field type or the collapsing-field type, meaning that the secondary winding which steps up the voltage is excited when the electrical field around the primary is expanding or contracting, respectively, in a process known as mutual induction. Testing the coil can be done with a multimeter and basic mechanical skill. Isolate and de-energize the coil. Remove all wires connected to the coil, then unbolt it from the engine. Check the primary windings for continuity and resistance. Set the meter to continuity (buzz box) and touch the probes to the two posts that feed the primary winding. There should be continuity. To
