I have snapper tractor with a 14 hp kohler with I/C OHV that quits after about 20 minutes or less if the air temp is warmer. When it quits it now longer has any spark. If I let if cool down for 30 minutes it will start up again. Any ideas?
try an autolite plug for ohv engines. get em at advance auto. those champion plugs crap out like nothing. when a plug that is bad gets hot it will not spark. found that on another engine. got hot cut off, let it sit for a little then started then cut off again so i put a new autolite in it and it doesn't do it anymore.
To me it sounds like your ignition is breaking down under heat. Most likely it is the condenser. Check into replacing the points and condenser. Now if you have electronic ignition then you'll have to check into the electronic coil to see if that is what is breaking down.