LOST SPARK ON ONE CYLINDER-----WHY

[dr1979-340]

I last had the engine running in Sept.  I ran it for about 1/2 hour and all was ok.  I went to start it Saturday and it fired right up.  The rpm's were high, probably because of the new throttle cable I installed, so I shut it down.  After restarting it, it ran for about 20 seconds and then quit.  After some testing I found no spark on one of the plugs.

I ohm'd the coil and the exciter coil out according to the shop manual and found both to be right on spec's.  It says to check the points and condenser next.  Am I on the right track?  I hate to tear that all apart if it's something else.

1-29-15 Update:  Last night I switched the two internal coil wires (white and red) around and I had spark through the external coil and plug.  It narrowed it down to bad internal coil, points or condenser.  I'll be getting a puller this weekend to get to those parts for testing and replacing.

[rminier]

This may turn out to be something that is a pain, but there is something real easy to try first, if you haven't done this. The spark plug caps unscrew from the spark plug wires. Trim about 1/4" to 3/8" off the end of the wire with some sharp cutters, then screw the caps back on firmly. This allows the internal screw in the plug cap to thread in to some nice, new, shiny wire.
  If this has never been done to your sled, it may work. If no one has ever done this on your sled, you should have plenty of spark wire to trim that little bit off, and still have plenty of slack.

[dr1979-340]

I tried that yesterday.  I did exactly like you describe with no difference.  The shop manual tells to ohm out the wire from the spark plug cap to ground.  It ohm'd out correctly.

[Boomologist]

Have you put a NEW spark plug in place of the one that lost spark? Sometimes they will short internally.

[dr1979-340]

Yes I used the good plug that sparked on the other wire.  Thanks.

[bbap]

Swap out the two coils and see if the problem follows the coil.  Steve

[dr1979-340]

Thanks Steve.  I'll try that.

[dr1979-340]

Turned out to be a defective condenser.  Replaced it and it is up and running again.  Thanks.