While flying the downwind leg for a full-stop landing, the pilot reduced engine power to slow the airplane for landing. When the pilot advanced the throttle, the engine did not respond. The pilot turned the airplane immediately for the runway. Due to the "tighter" pattern and increased airspeed, the airplane floated during the landing. When the airplane touched down on the runway, there was insufficient distance remaining for the airplane to stop on the runway. The airplane departed the end of the runway and the pilot ground looped the airplane to stay on the airport property. Substantial damage was sustained to both wings. An examination of the engine revealed that the clamp securing the throttle controller end was allowing the cable to slip freely.