Wayne - here we go again.
I believe Kohler always spec'd the spark plug gap at .035 but IH spec'd it at .025. I tried to research this before and it seems to be something to do with "where used application" (garden tractor in our case). It's hard to find this from Kohler any place but it's out there somewhere. I believe .025 is correct for a garden tractor engine.
Now, about your intermittent problem - as you can see already you're getting varying opinions of what it is. I doubt the plug gap had anything to do with it dying, and if I read your post correctly I don't think you did either, it was just something you discovered and corrected. Since most everyone knows I'm more of a shade tree mechanic (parts replacer) in my opinion it could be the condensor (cheapest item to replace first), next on the list is verifying the wiring isn't broke someplace, and the plug wire itself, next is checking the points, and finally the coil. Marty mentioned a safety switch, but I think that only comes into play for starting, not running - but my tree might be a little to shady here.
I think you already knew these things and just thru this out for suggestion. The thing about it that's nice for me is a reminder of what it could be.
Aaron W - HELLO out there to another Washingtonian. Don't do anything with your 149 amp gauge if it shows charging when running. You probably have one of the good gauges. Most of them bounce all over, and sometimes fairly stable at certain engine speeds.
David S - I just can't let your seat situation go. I said your 126 was perfect and it is. I should have mentioned I don't know how many I've seen where the spring are installed upside down, or even reversed so the open part of the spring is towards the front. And then there are those large flat washers that some people place on top of the bottom loop of the spring. I just can't believe some people can't see and think thru where and how these hardware items should be installed - or even just look at a pic on the Op Manual.