For those of you running the Kenai what pitch prop are you using? How heavy is your boat/motor set up?

I have an 18ft Lowe jon boat with a 40hp four stroke and am looking at trying a different prop? The boat is light (but maybe a little tail heavy with the 4 stroke) and I currently have a 12 pitch prop. I am thinking about trying a 13 or 14 pitch. Any thoughts? I don't have a tac.

Also.... As I race up river (and down) there is a spray of water (3' or so) shooting straight up right behind the transom, kind of like having your garden hose on a high pressure mist. This water is not part of the motors cooling system. I heard that it might be my prop Or it might be that the motor is sitting to deep in the water Or that I need a hydrofoil/stabilizer?

Any thoughts or related experiences would be appreciated.