prop

[Ms Luna 01]

What size prop do I need ? I have a 2003 2 stroke, 50 hp. yamaha, it's on a 16 ' check mate. It has a 11.6 x 11 on it now, rpms. 4200.

[TownsendsFJR1300]

What size prop do I need ? I have a 2003 2 stroke, 50 hp. yamaha, it's on a 16 ' check mate. It has a 11.6 x 11 on it now, rpms. 4200.

Go to this site, it should be helpful:

Performance Bulletins | Yamaha Outboards

[99yam40]

I do not know what a Check Mate is so looked up on web.
Did not find anything about that small of a boat, only a lot larger.

Could be the boat is heavy and is way under powered with a 50.
What does the plate say the max HP boat is rated for?

11 pitch prop is a low pitch and you are not getting to the proper WOT RPMs.
Could be a motor problem, a set up problem, or boat is just too heavy due to water in hull