Posted by John T on November 05, 2012 at 14:47:53 from (126.96.36.199):
In Reply to: Wico X Mag posted by Buddy Woodson on November 05, 2012 at 13:09:17:
A simple low voltage ohm meter test will tell you if its really BAD (like the LV Primary or HV Secondary is open) but it cant tell you if its really GOOD since many failures involve High Voltage Breakdown and/or occur only after its warmed up and under actual operating conditions. The LV Primary is less then 1 ohm while the HV Secondary is several thousand ohms and if either is open its obviously bad.
The most common cause of mag failure to spark is the points are burned or pitted or even gray oxide coated any of which kills the spark. You might clean n light file them and gap them n see if that cures the problem and replace if badly burned or pitted. Likweise a bad condensor can cause no spark.
Since points and condensor are relatively cheap compared to the coil if the coil passes both continuity tests and doesnt appear or smell burned Id suspect points and/or condensor first.
For the impulse cranking spark to happen the mags wind n trip spring assembly has to be working and it yields a good sharp SNAP each 180 of rotation otherwise no spark at cranking speed.
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