donlynn
Key Veteran
Location: New Zealand
| Gidday
Some checks i do to prove a ignition coil is faulty.
static tests
Visual
look for cracks in the case
look for track marks in the case ,it can look like a wiggly pencil mark
continuity
use a ohm meter and check the primary resistance, one lead of ohm meter to wire the other to frame , I have no idea what a gasser coil shouild be but it might be around 5- 100 ohms
use a ohm meter to check the secondary, one ohm meter lead to wire ofr frame the other to the spark plug cap then remove the cap and check directly to the ht lead(spark plug )
again I have never checked a gasser coil but it might be 1000 - 10000 ohms.
do the above tests while heating the coil with a hair dryer or paint stripper , to much heat will melt the plastic, you'll find the resistance readings may increase a little say 1-5 % thats ok but more than that I'd be suspicious
running output test
Snap on make a spark tester that is brilliant , you wind out the knob on the end to increase the gap, I'd reccomend not going above 8mm or the spark may jump internally inside the coil breaking down the internal insulation.
Do the above while heating
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Kill switch
As Al said is the kill switch crook ?
Is the wire for the kill switch chaffed against metal anywhere including the kill switch wire ?
confirm this by disconnecting the kill switch, be carefull as if this is the problem it will now start and you will only be able to stop it by throttle position so check this is possible before attempting start. often older m cycles will track across the kill switch after time leaving a carbon trace and cause leakage loosing spark potential.
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pick up coil
running test
use a ac voltmeter connected to the kill switch wire while the switch is in the run position and confirm you are getting a voltage while cranking , my guess would be 5-50 volts ac, faster engine speed the higher.
static test
use a ohm meter again and check pick up coil resistance with coil and kill switch disconnected, maybe 50 - 1000 ohms
please note all the values given are guesses, confirm with the manufacturer for the values or a mate who has a runner.
If I can help further please advise.
regards Don |
