Kawasaki 20HP runs 10 minutes then acts like it's starving for gas

I have a Cub Cadet RZT 50 with a 20HP Kohler (Kawasaki) engine. It runs just fine for about 10 minutes then acts like it's starving for gas. It will bog down, run fine, bog down, run fine. It will do this between 10 and 30 seconds until it finally shuts down. Then you have to let it rest for about 5 minutes. It will start up and run fine anywhere from 2 minutes to 10 minutes before it does the same thing all over again. I've replaced the fuel and air filters. I've replaced the fuel pump and cleaned the carb bowls, checked the Gas cap.... Still runs the same... PLEASE HELP!!!