yamaha F15 prop size

[htdawg]

Hi,

I have a 1999 yamaha F15 4 stroke long shaft with a 9 1/4 10 1/2 prop on it. could you tell me what size prop i could put on it to get a little extra top speed out of it? without killing the motor
p.s
its on a 13 foot fiberglass fishing boat

thanks
htdawg

[colossus]

You need a tachometer to measure the RPM.

[Ken]

htdawg,
You could just try the next size pitch up from 10 1/2 (?) to see if you get more top end, but you may already be pitched to the max for that load.
Like colossus says, you would need a tach to see what rpm you turn at WOT to see if you are at the top of the recommended rpm range as listed in the owner's manual.
Good luck [img]smile.gif[/img] ,
Ken K