Hope you didn't try to load up those nice new Yammis before breaking them in properly.
With a light to moderate load, the propellers should be selected (i.e. diameter and pitch) so that engines come up to the upper end of the rated RPM range. Based on what you wrote, the pitch is too high, but that doesn't seem right.
Is the boat heavily loaded, fuel, water, extra "stuff"?
2002 GW Islander 270 - 2001 Yam 250 OX66. Fishin' & cruisin'