What was found
PILOT STARTED ENGINE FOR TAKEOFF. STARTER CONTACTOR WELDED IN THE 'ON' POSITION. WHEN PILOT RELEASED KEY, STARTER CONTINUED TO RUN UNTIL BURNED UP. PILOT WAS NOT AWARE OF CONDITION. SUBMITTER STATED THIS IS A FAIRLY COMMON OCCURRENCE WITH 24V STARTERS ON CESSNAS WITH LYCOMING ENGINES. IT ALWAYS DESTROYS THE STARTER, AND SOMETIMES THE ALTERNATOR AND BATTERY. SUGGEST FUNCTION LIGHT BE INSTALLED IN CIRCUIT.