i have a 23hp kawi engine on a exmark ztr. once the engine heats up it has a problem starting. its starts up fine in the morning. i put the throttle and choke up and the engine just wines and doesnt kick in. i turn the fuel off between propertys, thought that might fix it. it sounds like a car that wont turn over and just makes that waaaa, waaa sound (haha) dont know how else to explain it.