For the first 5 hours do not run a constant RPM. Vary the RPM’s every 5 minutes or so. Do not exceed 75% throttle for the first 5 hours. Shift into forward and reverse a minimum of 10 times in the first 5 hours. For hours 5-10 you should do short runs at full throttle. After 10 hours normal operation can resume. Change the gear lube between 10 and 20 hours.