propeler pitch - please help!

[cpescar]

hello, please help me :
i have standard propeler 9,25 diameter / 9 pitch to my mercury 15 hp four stroke (model year 2010), is a problem if i change this propeler with the same tip of propeler but with 10 pitch / 9,25diameter? it is posible to kill my engine? low rpm can kill the engine components?
thank you! and sorry for bad english!

 

[jerryjerry05]

Re: propeler pitch - please help!

The only thing you might do is increase the gas consumption and get lower speed and lower the rpm's.
It might get a bit better take off but I doubt it.
You won't kill the motor.

 

[steelespike]

Re: propeler pitch - please help!

I think we need to know what you want to accomplish. What size boat and the typical load?
How is the present performance? good hole shot?
When thinking of a prop change you should use a tach and a gps for speed.
Little 4 strokes need to be propped carefully near the top of their rpm rating,6000 in your case.

 

[cpescar]

Re: propeler pitch - please help!

my boat is 5 meter long / 1,37 lenght, 120 kg.empty -( 200kg with me) the problem is when y run at full throtle (5400)the boat is like a plane to take off , for this prob. i give to engine hydrofoil, and the bow is better but not ok (ideal), and propeler wather jet is like a mountain and close to the boat (trim is tested in all pozition).a big power to engine 20hp ( now have 15 hp) will resolve this problem?

 

[steelespike]

Re: propeler pitch - please help!

"like a plane to take off" Do you mean the bow bounces up and down, or is it in the air. What brand of motor?
Some motors have a shallow water drive. It allows the motor to run be set at an angle to run in shallow water
yours may be stuck so the motor can't be trimmed at a normal angle.