I have a 3YM30 with almost 900 hrs. I run typically at 2750 (the recommended optimum), but have run all day at 3000 quite a few times. I have a 3-blade MaxProp set at 16X11 and the reduction gear is 2.62:1. The boat is about 19,000 lb. The RPM peaks at about 3500 (indicated RPM) under load and drives the boat at about 6.8 kt in smooth water when the bottom is clean . Hull speed is 7.7 kt. This is a sweet engine and I have had zero problems with it.
Never sail closer to the wind in degrees than your age
Last edited by FishSticks; 10-14-2010 at 08:09 AM.