What was found
ON CLIMB-OUT FROM LIT NR 1 START VALVE LIGHT ILLUMINATED. SHUTDOWN NR 1 RETURNED LIT. INSPECTED STARTER, CLEANED CANNON PLUG COULD NOT DUPLICATE PROBLEM. AS A PRECAUTION REPLACED START VALVE. ON A SUBSEQUENT FLIGHT START VALVE LIGHT ILLUMINATED MOMENTARILY AFTER TURNING ANTI-ICE AND IGNITION SWITCH TO OFF. NO FURTHER PROBLEMS NOTED. FOUND NR 1 ENGINE START/IGNITION SWITCH SPONGY, WOULD NOT LOCK IN OFF POSITION. REPLACED START PANEL, OPERATION NORMAL.