Prop Recomendation for Yamaha 115hp

[gearyg]

Hello, I have a 2002 4-stk Yamaha 115hp on a 210 CC. I know I am under powered, but this is what I have. Currently, I get 28mph WOT and it sounds like it is topping out...the engin reves faster, but no more speed. I read that some others (with similar load size) hit the mid to upper 30's. Could a Prop add this much to the top end? I guess, I am looking for the best of both worlds, faster top end and better milage. Any recommendations out there? Anything else I should consider? I currently have the factory stock prop....thanks.

 

[WillyBWright]

Re: Prop Recomendation for Yamaha 115hp

The factory ships those without props. The dealer installs the appropriate prop based on the boat. The correct prop will allow the motor to reach maximum recommended RPMs at full throttle with an average load. If your motor is unable to attain 6000 rpms, you might need a prop with less pitch. That might seem like going backwards when going for speed. But the motor needs those RPMs to develop full horsepower.

Right now the most important numbers we need are the pitch of your prop and your top-end RPMs.

Just a guess, but I'd think about a 15p on yours would be a good starting point. I assume you have an aluminum prop. You can usually go up an inch (maybe two) compared to an aluminum by going stainless. 16 would be my guess in a stainless. Stainless almost always goes faster than aluminum. Stainless is also much heavier and unforgiving so there can be consequences to the drivetrain.

 

[troypolla]

Re: Prop Recomendation for Yamaha 115hp

I have the same"05" 115 4 stroke. It has a 15p prop. Power Tech I think. My top is 38 at 5800rpm. What is the WOT rpm? What prop pitch do you have now, and how much does the rig weigh.

 

[troypolla]

Re: Prop Recomendation for Yamaha 115hp

8)

 

[gearyg]

Re: Prop Recomendation for Yamaha 115hp

Well, this is what I got off of my prop markings

It is a White Prop
GE-5
19K
Y-2
13X 19-K

Not sure what this all means...any ideas?

 

[gearyg]

Re: Prop Recomendation for Yamaha 115hp

Forgot to add, it weighs 2,800 to 3,100 loaded on the water.

 

[troypolla]

Re: Prop Recomendation for Yamaha 115hp

I assume that its a 13p prop. What are your WOT rpm with that load? You should be 5000-6000 range but need to be at the upper, around 5700-5900. My rig is about 2500 loaded and hits 38 mph at WOT. Please post your WOT so we can help ya out.

 

[kp913]

Re: Prop Recomendation for Yamaha 115hp

From what you described you have a 19 pitch Aluminum propeller.

www.propellerforum.com

 

[troypolla]

Re: Prop Recomendation for Yamaha 115hp

please post wide open Throttle

 

[Rancherlee]

Re: Prop Recomendation for Yamaha 115hp

If it is a 13x19 the diameter is too small also besides the pitch being to steep. What you are probibly doing with a heavy boat is spinning out the prop at around 28mph which is why you see the rpms climb. You have a pretty stout gear ratio of 2.15

 

[kp913]

Re: Prop Recomendation for Yamaha 115hp

Sounds like the hub may be spun in the 19 pitch.