Is this a BRAND NEW machine? If so, there is a blurb about it in the Op's Manual. It says not to run engine at WOT and to vary the RPM's for the first 50 hours. I am up to 32 hours as of yesterday. We have a large yard so I change the throttle position as I complete each round. I run anywhere from 2,800-3,100 RPM's. Not much of a range, I admit. However, I feel like I am in compliance with Kubota's break-in procedure. Eighteen more hours and all of my mowing will be at 3,200-3,300 RPM. I realize that 3,200 is not wide open but, it's close to it. Is this at all important? I seriously doubt it. That being said, you only get one chance to break in a new machine so I am trying to be patient. Loader work has really helped me to pass the time on the hour meter. Easy to perform a variety of tasks and run the engine speed anywhere from 2,300-3,000. All I can say is, be patient but run it as you see fit.