Small Engines (Lawn Mowers, etc.): Kohler CV14S Stalling problem, valve clearances, spark plug

Question
I have a Kohler model CV14S engine on my riding mower.  I just started experiencing a problem with the engine stalling when it gets hot.  It starts fine and runs good for about 15 minutes and then it will start to "sputter" and stall.  I can shut if off and then after a few seconds it will restart but as soon as I start to mow it will do the same thing again.  If I let it sit and "cold soak" it will start right up and run fine again until about 15 minutes into the run and then the same problem.  Tank is clean, new fuel filter, spark plug looks good.  Any ideas?

Answer
I would start by replacing the spark plug.  When it stops, replace the spark plug with the new one and see if it starts.

The first thing to determine is the problem, fuel or ignition.

When was the last time the valve clearances were checked?

Did you download the service manual for Kohler's website?

Eric