Kohler engine

Thanks, for allowing me to jump on board. My problem is with the engine revving up and down on it's own. I bought a carb kit, gaskets and o-rings and it did not improve it. It will start and run it just revs up and down even at full throttle. But when I kick in the blades it runs smooth. It a Kohler SV735-3022 (26hp)

Thanks for any help.