I have an 07 cub cadet with a 22 hp Kawasaki engine. has been worked to death on our rough property. never failed because it do work to keep it in good shape. suddenly this season its working fine for 20 to 30 minutes and then I must pull the choke to keep it going and its difficult even then. let it cool off and it goes again. I went into the carb and it was as clean as new I went ahead and replaced a couple of o rings. same issue. then I replaced the plugs same issue. then I replaced the 2 coils. same issue. helpppppppp. thanks kelly