Do I have the correct prop????

WaterDR

WaterDR

Senior Chief Petty Officer
Joined
May 8, 2012
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730
I have a 2012 Sylvan 8524 LZ RPT pontoon with a Yamaha F-115. Brand new. Dealer equipped it with what I think is a 13 degree prop, but may be a 13.5. It is a white, standard issue, Yamaha prop.

With the motor tilted all the way in the water, and with just me on it, it will hit 6,000 rpms at WOT. As I plane the boat, it will go a bit over 6,000 rpms, so I have to throttle back a bit. Dealer claims that this is the perfect prop based on this. Naturally, as I add weight, I suspect the rpms will drop. Dealer claims that 6,000 rpms is fine. Rev limiter is at about 6,200. I am wondering if I should go with a 15 degree, or if the rpms will drop too low when fully loaded.

Any thoughts?
 
S

steelespike

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Apr 26, 2002
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19,069
Re: Do I have the correct prop????

As far as responce to additional weight I too would say its perfect.I have a feeling your not likely to be running alone much.
If you go to a 15 you could lose as much as 400 rpm. The addition of weight could take you out of the rpm band quickly.
If your worried about someone else running over 6000 put a big sign near or over the tach.
 
WaterDR

WaterDR

Senior Chief Petty Officer
Joined
May 8, 2012
Messages
730
Re: Do I have the correct prop????

Looks like my wife and daughter need a lecture :)
 
BobGinCO

BobGinCO

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May 22, 2012
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Re: Do I have the correct prop????

steelespike said:
If you go to a 15 you could lose as much as 400 rpm. The addition of weight could take you out of the rpm band quickly.
Click to expand...

Or it could be much worse. BTW, that's not "degrees", it's inches of PITCH (as opposed to diameter).

I had a 15" pitch prop on my Merc 115, and could only get 4800 RPM out of it, and with a 13" pitch prop, I'm getting 6200 out of it. Right where the engine manufacturer says it OUGHT to be.

Note: This is at 6,000 feet elevation. The point is that a 2" change in pitch gave me a 1400 rpm change - NOT 400 rpm.
 
WaterDR

WaterDR

Senior Chief Petty Officer
Joined
May 8, 2012
Messages
730
Re: Do I have the correct prop????

Oh....somany issues. I was gonna try a 14, but decided to stick with the 13 that I have.
 
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