I know other factors can influence, but assuming your prop is in good condition, I would try a 19" pitch.
I run a 5.4m rib with Honda 90 outboard and 12.5 x 19 4-blade prop. I top out at about 36kts @ 5,800 which is right in my max rpm range.
My friend runs the same rib and experimented with a few different props, including a 17" pitch. He had the same issue as you with over-revving and low top end. He settled for a 13 x 19 3-blade and gets similar performance to me.
Hope that helps
Happy when wet!