Ignition coil problem

[rek58]

Well it started out with a plug fouling (right front). I had been messing with the carbs and after the fouling happened, re-synched them( of course they were off). Figured that was the problem. Put in a new plug and off I went. Happened again. Being on the highway helped keep it clean, but definitely not running great. I figure it's one of two things, a carb problem or a firing problem. The coil and plug wire are easier to check. Plug cap came back within tolerances, primary coil readings were ok but definitely on the high side. Didn't get a needle quiver for the secondary (not looking at the manual, not sure if that's the correct name) test. So I am going to assume that it is the coil or possibly the wire. Anyone else have any thought on this?

[pegscraper]

It sounds like the coil is worth pursuing further. It's not common, but there's been another member or two around here who had a coil go bad. You might try swapping that coil with a coil from another cylinder and see if the problem follows the coil or stays with the same cylinder. Just one advantage of having multiple coils. That should help you isolate the problem.

[Gearhead]

You said you measured the cap OK. Did you unscrew it from the end of the plug wire? Then did you measure secondary resistance from one of the coil terminals to the exposed end of the plug wire where the cap goes?

1. Are you on the correct meter scale? Should be at least a 20k ohm scale.
   
2. Can you see corrosion on the copper wire strands at the end of the plug wire?
   
3. There could be corrosion on the other end of the wire, where it goes into the coil. This corrosion could be enough to register no continuity, but a spark could still jump across it intermittently. The wire comes out of the coil pretty easily
   

Jeremy

[rek58]

Meant to get back sooner on this with a reply. It was the coil, everything is running fine now. Got very lucky on getting a replacement. Had the part # when I was calling around, no stocks the thing around here. One dealer showed one, he says " I really doubt I have it, but I'll check". Comes back a minute later, "It's here". Changed it out, new plug, good to go.

[Gearhead]

Well, good news!

 

JEremy