Need more RPMs out of my Yamaha F150

[ICHTHYDEMON]

I finally got time to take my 2006 North River Seahawk out over the weekend. I have a F150 and at WOT I'm only getting to 5000 RPMs. I tried various trim positions and never got more than 5000 RPMs.

The recommended operating range is 5-6K but the 150 makes all 150hp at 5500 RPMS. I'd like to get to at least 5500 if not closer to 6000.

I pulled the prop and found its a 14x19. I called the guys at NR and they'll switch the prop to the right size. I know a 2" decrease in pitch will gain 3-400 RPMs. A 17" prop will get me to about 53-5400 RPMs and a 15" should get me to 57-5800. Would you go with a 17" or 15" pitched prop?

[Tacklebuster]

I had a 19 on my 05 21' Seahawk with the 150. I could only get a touch over 5000 RPM's when trimmed up.

We put a 17 on her and all is well. She will spin 6000 RPM's under the right conditions when you trim up the motor. The 150's needs the 17 on them.

You will get close to 6000 with the 17, you'll be surprised. The 15 will over rev you

You will also gain a few hundred RPM's as your motor breaks in more. Trust me on this, I was in your shoes not that long ago.

[Starfish]

I'd be inclined to try the 17 first also, especially with some tip cupping. Then if you still need a few hundred RPMs you can raise your motor up a hole or two and see if you still stay hooked up... you'll pick up a couple of hundred RPMs for each hole.

[ICHTHYDEMON]

It sounds like the 17 is the way to go. Thanks.

[OTH]

I had the same problem with my Seahawk. I put on a stock Yamaha 17, and the 19 is now my spare. The 17 is the way to go. RPM's are perfect now. Right around 5600, and I think I picked up 1 or 2 MPH. Huge holeshot difference too.

[retaliate]

Recommended operating range is 5k to 6k?, that would be max. recommended operating range, red line is probable just above 6k, altho max hp is probable about 5.0k, max torque is less, probable about 4.0k which is what I set my max. cruising rpm at, & only go over that for a short time, if you want your motor to last don't run high rpm for long periods. Max. torque is also max. performance(fuel comsumption, power, & durability), of course all motors, & boat's are different, as well as load, wind, current, swell,& saltwater which is heaver than freshwater, & climbing the back of a swell with a full load of fish, & passenger's will let you know if your prop is correct, many of us have gone to a smaller prop just for ocean use, usually one size smaller is adequate.