I HAVE BEEN TOLD BY MY DEALER THAT IS TAKES TEN HOURS TO BREAK A MOTOR IN, I ALSO READ IN A MANUAL FOR A 1984 9.8 MERC THAT IT TAKES ONLY ONE HOUR.<br /><br />ALSO YOU ARE NOT SUPPOSE TO LET IS IDLE AND YOU ARE SUPPOSED TO VARY THE RPMS, AND NOT DO FULL THROTTLE AND RUN DOUBLE THE REGULAR OIL RATIO. THEN AFTER THE TEN HOURS IS UP I HAVE TO TAKE IT BACK TO THE DEALER TO CHANGE THE LOWER UNIT OIL.