what propeller would good for my boat

[Rob1976]

I have a 24ft pontoon boat with a NS40C nissan outboard motor i am wanting to buy a new prop what is a good size for that boat. i was told a 11.4/12/3 not wanting to go fast just cruise around and enjoy being on water with friends

 

[steelespike]

Re: what propeller would good for my boat

When propping a motor it needs to be able to reach its max.wide open throttle rpm.5500 for your motor.
Your wot rpm and gps speed will help tell how your setup works. We need your present prop size usually under the prop nut
or near the base of the blades.I think your motor has a 1.85 gear ratio and if so I think a 9" pitch is closer to what you need.

 

[Sea Rider]

Re: what propeller would good for my boat

Must go for a wot spin with you alone and lightly loaded pontoon boat on flat calm glassy no wind waters and check max achieved wot rpm. To know is engine revs happily inside safety factory stated min-max wot parameters. Will need to install and induction tach to test if under or over propped for that combo. 40C revs at 5200-5800 wot rpm.

When you prop a combo at around or max rpm, rpm will drop accordingly as you start adding weight, with a tach will know how much rpm will lose when light, medium fully loaded. You can even maximize your prop to achieve near max wot numbers if family oriented. Once you have dial best prop pitch you can throttle throughout the hole throttle range in peace, propping for max wot doesn't mean that you have to run wot all the time. The engine will run happily and safely in the event you must go full throtttle.

Tohatsu standard 11 pitch delivered prop on light applications usually delivers near full wot rpm, will need to go for a 10-9 less pitch if engine works on a heavier application. Go for a induction tach, a must have one,

Happy Boating