Prop Pitch

[Reel Kahuna]

Am I okay with a 19 pitch prop WOT at 5K rpm on my 19’ Bayrunner Baja 2001 Yamaha F115 or should I reprop? Max water speed is 40 mph which is really too fast for this old man .

[99yam40]

speed if not the right way to measure correct prop, RPM s are.
seems your WOT rpms are too low, you are lugging the motor.

have a look here to see what a rig like yours did and what prop they used
Outboard Performance, Performance Bulletins | Yamaha Outboards

[Reel Kahuna]

Nearest boat listed is the Starcraft w/19 pitch. I think I'll have to drop down to a 15 pitch to attain 6K rpm .

[99yam40]

what elevation are you running this boat and motor at?
you loose power the higher you go and end up with less prop the motor can turn

[Reel Kahuna]

I'm at sea level at the Pacific Ocean but tested it on a Lake here in California also at sea level.

[99yam40]

I know not what to say as to why you are not able to push that prop unless the motor , boat, or set up has a problem.
Maybe the boat is different enough in weight or hull design.

Yamaha makes test props for their motors you can run in a tank or while boat is tied off to dock or trailer to see if the motor can hit certain RPMS.
maybe you can have a Yamaha shop close to you test if they have the correct test prop

[Reel Kahuna]

I spoke to a prop shop who said that for every pitch changed it will increases/decreases the the rpm by 200. So I bought and changed from a 19 to a 13 pitch prop. Tried out yestereday and hit my 6K rpm. I'm a happy camper...err boater .