I have a 1999 Honda BF90 pushing a 17' Hurricane (approx. 1300lbs empty). The motor has a 15" pitch prop but still can't manage to get above 5,000rpm at WOT and performance seems a little sluggish. I am being ****n into weeds by the same boats fitted with ten year old 75hp motors.

Is there anyting obvious that might be limiting my performance? I bout the boat last year and supposedly, the motor was fully serviced. It starts and runs great, with no misifres etc. Just seems to lack a little oomph.

Any help would be appreciated.

You might try a 13 pitch prop, it will increase RPM's and hole shot but give you any more top end. The RPM range for that engine is 5000 to 6000 RPM's.

I had a 90 hp Honda same year on a 2000lb+ 25 foot boat I ran the largest prop I could fit with a very low pitch and round blades it revved out to 6000 perfectly and did 29 knots. I now have a 130 hp honda on the same size hull at does the same speed 29 knots butt takes more fuel it has a 4 blade ss standard pitch prop. sorry I cant give you specific dimensions.
but your prop dealer should be able to help you if you give him this info.
the 90 is a great motor with a good low gear ratio and is able to swing some big metal.
Good Luck.