What was found
AIRCRAFT RETURNED TO PLATFORM AS A CONSEQUENCE, DURING LEFT ENGINE STARTED, THE START VALVE OPEN LIGHT DID NOT TURN OFF. THE CIRCUIT BREAKERS WERE RESEATED, CROSS FEED AND CONNECTORS WERE CHECKED AND FAILURE CONTINUED. THE REPORT WAS DEFERRED IAW MEL 80-1. DURING TRANSIT SERVICE START VALVE WAS REPLACED IAW MM 80-10-02, TESTED CORRECT. DEFERRED REPORT WAS CLOSED.