My guess is your tach is wrong. Boat would not even plain off at 2300 rpms
(chances are).
Also at 2300 rpms w/ a 21 pitch prop your speed would be (assuming a 2:1
gear) would be 20 mph max and probably more like 18.
Buy a cheap automotive tach from the parts store and hook it up. My guess
is your at 4000 rpms if not more.
Having said that, you probably need a 19 pitch prop. 4 blade would be good
for your rig in trying to ski and stuff. SS is always better.

Tony


"Joseph" wrote in message
...
I have a 1998 17ft Larson 176 SEI bowrider with a Volvo Penta SX Cobra 3.0
Liter with 130HP. I have a 3 blade alum. prop, which is 14 1/4 x 21
pitch.
It is lightly pitted and has very minor damage to it. At WOT my RPM
gauge
reads 2300 with a top speed between 33-36 MPH in fresh water. My owners
manual states that the recommended operating range at wide open throttle
is
between 4400 - 4600 RPMs. This is a big difference in RPMs. I have
trouble getting skiers up and have played with the trim and weight
distribution to no avail. Should I get a 4 blade, larger diameter, or
lower pitch prop? What else would cause it not to plan or reach the
recommended WOT RPM range? Thanks.