I promised when I got this fixed I would post the results.
Last fall, I was having trouble with my lawn tractor and posted about it. The tractor would run for about a half hour and then just stop. It would have to sit for two or three hours before it would start again. This machine has a 15 hp Kohler engine in it.
I got through the last few mowings last year without ever getting it fixed but when I went to mow for the first time this year it didn't want to start but finally did. It ran for about 20 minutes and quit. I let it sit all night and tried to start it the next day and it would not start at all.
But this year when I pulled the cover off of the engine I noticed the likely problem right away. It was the magneto or what we used to call the coil. I don't know how I over looked that last year. It has been a while since I have had to work on an engine. I replaced the spark plug but completely ignored the thing the spark plug wire ran to.
Oh well, it's fixed now at least.