Motoplat ignitions consist of both circuitry and wound wire, and therefore resistance testing is not accurate. We test Motoplat ignitions on a Motoplat Dynomometer which performs function tests to measure the output voltage, wave pattern and spark strengths. Rotors/flywheels are remagnetized as part of the testing process. The lower magneto is tested at room temperature. If the unit tests good, it is then heated and tested again. Parts that test bad are not repairable, and so would need to be replaced with new parts. The manufacture of Motoplat ignitions ceased in 1993, and few replacement parts are available now. When you suspect that your Motoplat Ignition is not functioning properly, there are a few procedures which should be followed before sending it to us. First, check to see that all mechanical grounds are solid and rust free. Corrosion and rust can cause a deterioration of the ground circuit and in time destroy the ignition. These grounds include: (1) coil to frame; (2) engine to frame; (3) mounting plate to engine cases; and (4) stator to mounting plate. Also, while less thought about, but still part of the grounding circuit for spark is the path of current from the engine cases, through the cylinder base and head studs, to the spark plug. If these are allowed to get rusty and corroded, it can affect the ignition’s operation.