Kohler 22 HP 7000 series problem

Have this engine on a Toro 42 inch cut, time cutter 4225 ZTR mower with 19 hours on engine. Have been having this problem for a while.It starts perfect when it's cold. after mowing for a while 30 minutes .Go to restart ,it turns engine to start but can't get past one revolution. it hangs over and over trying to get past one revolution. Once it cools down, it starts perfect. Can't believe the valves are out of adjustment @19 hours on engine????

Battery Fully charged , Connections Tight.Alternator is putting out 14.3 volts at full throttle, it's not a Electrical problem, it's Temperature related to the engine Starting from Cold to Hot. My brother has a Kohler 22.5 h.p. 11 years old .I adjusted his valves  last year with the almost same problem and it fixed it. He ran 10 years without a Starting problem. My engine has 29 hours on it and the problem started @ 10 hours. Evidently some person didn't do their job correctly when my engine went by the assembly line Vale Clearance  quality assurance. Any way Thank, for the input. I don't think there is any warranty coverage since I'm the second owner of this Toro mower.

It is possible you have a bad starter that is borderline weak.

Yeah, I would check the valve clearances