Good afternoon,

Our Kitfox with a 2003 Vintage 912ULS & 400 hrs recently (last week) suffered an ignition problem. I'd like to check with the group to assure I am not overlooking something with my diagnosis.

A couple notes

A) Some time ago I switched to a narrower spark plug gap on Larry's advice where he has had better luck with with this modification - using 0.024"

B) The main battery was replaced within the last few months, not because it wasn't working, but because of it's age and a slightly lower float voltage

C) Fuel system including starting carb verified OK - it's getting gas. I know a starting carb failing to close completely can cause starting problems.

C) I have not done anything with the stator/pickups other than to assure the wires are OK and nothing is loose.

Here is the sequence of events:

1) On a cold start (70 degrees F ambient) a week ago the engine spun over vigorously without firing at all for much, much longer than what is normal. A second try and it finally fired and ran normally. Went flying

2) Two days later, (About the same ambient) it spun over vigorously without firing, gave it a rest, tried again with no firing; and, did it a third time with the same result. Time to hang it up and figure out what is wrong. Not flying.

3) Got some tools the next day and found that cranking with a timing light on all 8 plug wires, none of them showed any spark.

4) Took apart the panel to get the starting switch out and verified that it was working right, right and left grounds fine, the P leads were fine and the Module end of the P leads were connected properly.

5) The baffling part of this is why would a dual ignition system apparently die on both sides at the same time

6) Today, Based on some anecdotal reports on the web about these engines, put my parlor heater on the modules and warmed them up for about 15-20 minutes Engine fired up instantly and the timing light showed spark. Engine ran normally after that.

7) I am going to let it cool for a day, then go back and double check the manifold grounds for the modules (ULS has a separate lead going to two separate grounds on the manifold. I want to be sure that not only are the grounds at the manifold assured (checked them) but that the manifold has a solid ground to the block.

So question - Can anyone think of anything I have missed or miscalculated on. Modules are kinda expensive. Following this latest experiment with heating up the modules and having good spark, I now wonder if one module was weak all along and the second one decided to join it making it look like a double fail.

Any thoughts and comments welcome.

Thanks for you input.