what prop size?

[MWick]

I have a Yamaha F25ELHZ 4/stroke 25 HP. I would like to know if it is possible to up the HP? It has a 9 7/8 x 10 1/2 F prop on it. This motor is underpowered for my boat due to lake restrictions. I have installed [Smart tabs] on the boat which has helped get it up on plane.Can I change to a bigger diamiter and different pitch prop? I dont have a tack on the motor so
I dont know the RPM . I dont know the weight of the boat but it is rated for
a 60HP tiller. Thanks for any imformation. MWick

[boats.net]

You could go to smaller pitch prop but will increase rpm's at full throttle and may overrev if you are already running on high side of rpm range now. 8 Pitch prop is the smallest available for that motor, 2001 F25ELRZ Yamaha Outboard LOWER CASING DRIVE 2 Diagram and Parts