1) A low voltage ohm meter continuity test can tell you if a magneto coil is definitely BAD, such as an open circuit. If EITHER the LV primary or the HV secondary fail a simple continuity test, THE COIL IS BAD
2) HOWEVER just because BOTH the LV Primary and HV secondary are continuous and within the correct ohms range, THE COIL CAN STILL BE BAD as many coil breakdowns are due to HV breakdown especially once all warmed up WHICH THE LOW ENERGY LOW TEMPERATURE LOW VOLTAGE OHM METER TEST WILL NOT INDICATE.
3) Typical mag coil LV primary resistances are often quite low, say 0.5 ohms to under 2 ohms, while the HV Secondary is often several thousand ohms. Don't have a calf anyone, there are a lot of mags and a lot of mag coils and different resistance values so this isn't true for alllllllll freakin mags
If the coil doesn't pass the smell test or looks like its been hot, it may be bad even if it passes both LV and HV continuity.
More typical problems are the points or points adjustment or the condenser or the rotor has lost magnetic strength, but if that's all good??? sure its possible a coil is bad even if the ohm meter shows both windings are continuous and within the correct resistance range.
Its NOT GOOD to dry fire a Mag with no spark plug etc on the HV output cuz the voltage rises to higher then normal levels and may cause an arc or short in the HV windings with HV breakdown thereafter.
If a mag produces a hot spark when running or pull started but NOT when shes cranking, the impulse mechanism may be weak even if the coil and points and condenser are all good.
Got it???
John T NOTE I have gave Seminar Workshops on Wico Mags but Im NOT an IHC Mag man so no warranty
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