Prop choice

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Working4boating
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Joined: Wed Oct 07, 2015 7:53 am
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Prop choice

Post by Working4boating »

Hi, I have been looking at old posts and am hoping I can get some help here. I have a 2stroke 1980s 40hp mariner on the back of my 16 foot 6 Broom Aquarius speedboat. A little small but it'll have to do for now. I tested her for the first time on the weekend. I am only getting 11knots out of her at full throttle. I feel this is a little slow and so plan a tune up. This I am happy with but prop choice I have no experience with. The prop supplied is pretty shabby so I am looking to change it. The only markings on it is PR505 a sixth digit/number is unreadable. My thoughts are that the prop may be no good for my set up. Any thoughts on what my prop is and what prop I should receive would be gratefully received.

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Rapier
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Re: Prop choice

Post by Rapier »

Hi, if I'm right your motor is one of the ubiquitous 2 pot Yamaha-built versions? Am not familiar with the prop number, but as the Aquarius is a heavy boat designed for high Hp motors, it's very likely to be a too coarse a pitch problem, resulting in the motor bogging down and failing to reach optimum rpm. The motor might have been used on a lighter rig before and is probably over-propped, but I'd think at 40hp (even if at the prop) it's below the minimum rating for this boat.
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