What was found
AN EQUIVALENT AUTOMOTIVE SPARK PLUG WAS USED IN PLACE OF THE ENGINE MANUFACTURER-RECOMMENDED SPARK PLUG DUE TO LOCAL AVAILABILITY. AFTER APPROXIMATELY 25 HOURS, A ROUTINE INSPECTION CAUSED BOTH SPARK PLUGS TO BE REMOVED. THERE IS ONLY ONE SPARK PLUG PER CYLINDER AND TWO CYLINDERS PER ENGINE. THE FRONT SPARK PLUG, CLOSEST TO THE GEAR REDUCTION UNIT, WAS INTERNALLY BROKEN - THE METAL ELECTRODE INSIDE THE PORCELAIN HOUSING HAD BROKEN IN HALF AND WAS FREE TO FLOAT INSIDE.