What was found
THE FUEL SELECTOR VALVE WOULD NOT STOP THE FLOW OF FUEL IN ANY OF THE FOUR DETENTS (OFF-LEFT-BOTH-RIGHT) AT THE FIREWALL FUEL GASCOLATOR DURING AN ANNUAL INSPECTION. THE AIRPLANE HAD SAT IDLE FOR APPROXIMATELY 8 YEARS WITH THE FUEL TANKS FULL. AS I WAS ABOUT TO DISASSEMBLE THE FUEL GASCOLATOR TO INSPECT THE FUEL STRAINER I HAD POSITIONED THE FUEL SELECTOR TO OFF. I THEN ATTEMPTED TO DRAIN THE GASCOLATOR WITH THE PILOT-OPERATED DRAIN CABLE BY PULLING THE DRAIN KNOB. I WAS UNABLE TO STOP THE FLOW OF FUEL FROM THE GASCOLATOR BY POSITIONING THE FUEL SELECTOR VALVE POINTER KNOB IN OR NEAR ANY OF THE DETENTS. CESSNA SPARE O-RING KIT 0716613-200 IS LISTED IN THE IPC FOR THE INTERNAL FUEL SELECTOR VALVE O-RINGS.