What was found
(CAN) ENGINE POWER COULD NOT BE REDUCED BELOW 2300 RPM, THE THROTTLE APPEARED TO BE STUCK. ON THE ADVISE OF THE TOWER AND GROUND STAFF, THE PILOT SET UP AN APPROACH AND ONCE LANDING WAS ASSURED THE ENGINE WAS SHUT OFF BY SETTING THE MIXTURE TO IDLE CUTOFF. THIS WAS EXECUTED AND AN UNEVENTFUL LANDING WAS CARRIED OUT. POST-FLIGHT INSPECTION FOUND THE CARBURETTOR ACCELERATOR PUMP DISCHARGE NOZZLE HAD SEPARATED FROM THE PUMP AND JAMMED THE BUTTERFLY VALVE CAUSING LOSS OF THROTTLE CONTROL.