I have a new boat coming with a 250 Pro XS (sorry no serial number yet), and I have a general question on break in after reading everything that's been posted. It sounds like after 3 hours of running the boat up to 4500rpms I should do a full cool down/heat cycle. Can someone tell me how long that takes and/or how to tell when it's completed that cool down? I appreciate the help, as this is my first new engine and I want to make sure I'm doing everything correctly.