Prop size question

[Altro Cat]

I have a 96 Xpress, 17 ft with a 40 yamaha. I am getting a top speed of around 28 to 29 mph at 4300 RPM. At times it seems a little slow to get on plane so I was thinking of a lower pitch prop or a 4 blade.

Operating range for this motor is 4500 to 5500. I am currently running an 10 x 15 3 blade prop. What could I expect if I were to go to a 10 1/2 x 13 4 blade prop?? If that would not be a good choice what would you recommend?

[200090tlry]

I would stick with Yamaha

If your motor is 2stroke it's easy choice with K series. I had Solas on Mercury and fitment is not as good stock prop. Expect 250rpm more also check fuel pump you might get 500 more rpm if like my motor.