Motor Prop/Mounting height Question

[davides618]

I am running a 175 Suzuki on a 21 bay boat. The motor is mounted 2nd hole from top and running a 3 blade 16x23 prop. WOT trimmed out I turn 6300 rpm(Suzuki Max for this motor) with full tank of gas, all fishing gear and 2 large men in the boat. The cavitation plate is about an inch below the water. The dealer I bought the boat from said that is fine as long as I am turning my rpm. Another person told me I need to lift motor one hole and possibly a bigger prop. I would appreciate if anybody could give me some more insight before I bring the boat back to get serviced as to what really need to be done.