Lt for Life

OK I bought the boat last fall but I am just getting around to getting thing going. Ran the boat for two weekends now and I have not been able to get the RPM above 4100. 52mph on gps with full tank two adult and two small kids. I am spinning a Bravo 23" 3 blade prop. When I trim the motor excessively I can get more RPM but I loose speed on GPS. The chart from Baja says I have the right prop. But I think I should be getting more RPM out of the motor. Is it possible the RPM gauge is not accurate? Or do I need to try a different prop?

Also I had the local marina (resurface) ie. media blast and paint the outdrive. Not a pretty job. LOTS of pitting and a rattle can finish. Flat Grey What where they thinking? Could this be robbing me of RPM's or just speed?

Thanks

Lt.