I decided just for giggles to do a compression test on the motor I just pulled from my log splitter . Got around 50 PSI after about 6 pulls on the starter rope . That may be a good number if this motor has a compression relief device for easy starting . I haven't checked yet but plan to . And the new motor is doing just fine , hardly burps when loaded with a big log . What's a reasonable time to run the break-in oil ? I've got about 2.5-3 hours run time so far , varied RPMs and load and a couple minutes at idle before shut down . I'm thinking around 5 hours , 10 seems like a bit too long .