Axis Wakeboard Boat Forum

Haha, dude you are at sea level!

If you have ever gone backwards in diameter (say from a 15" prop to 14.5" or smaller) you would know that size definitely DOES matter. I tried going backwards from a 2315 to a 2079 for exactly the reasons you state -- to get the rpms up. Problem being in practical application, yes the rpms came up, but forward thrust was not improved (all slip all the time). Boat went to feeling like a camaro with bald tires in the snow. That was on a 2011 MB 23, but I don't see why the result would be different on a different boat.

Here's the torque curve overlay I was thinking of:

Really I think the best thing you can do is call one of the prop builders and explain them your situation. I'm sure you are not the first person with this problem.

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No codes in the computer - I checked

Check out the video I just recorded tonight. 35mph top speed. 5600-5700rpm running full throttle at top speed. https://vimeo.com/167829070

these are helpful I appreciate seeing the power curve differences in the motors. Kinda makes me wonder why didn't they do the 1.72 Trans for all motors?

The plan is now that I have all of the answers I think I need for Eric at OJ I'll give him a shout tomorrow and get his take.

Guys know that I REALLY APPRECIATE the help.

I agree with waynetuttle, I'd think a smaller diameter prop may help, the engine can't make enough torque to push the prop past 3500 rpm at that weight, a smaller diameter prop would give you more slippage at the same speed giving you a little more rpm and maybe the engine can horsepower past the hump you're hitting, see if your dealer can loan you a 2079 or 1615 to try out, if nothing else it's worth a try to find out, hopefully your prop guy can swap it for ya

[quote]Haha, dude you are at sea level!

If you have ever gone backwards in diameter (say from a 15" prop to 14.5" or smaller) you would know that size definitely DOES matter. I tried going backwards from a 2315 to a 2079 for exactly the reasons you state -- to get the rpms up. Problem being in practical application, yes the rpms came up, but forward thrust was not improved (all slip all the time). Boat went to feeling like a camaro with bald tires in the snow. That was on a 2011 MB 23, but I don't see why the result would be different on a different boat.[/quote]

There is always more to it than just changing the diameter, the pitch is also critical. To go from a 15 X 12 to a 14 X 12 would not be ideal since the water being thrown is not increasing. a 14 X 14-1/4 might have been a nice balance between reduced shaft load and increased thrust. At these speeds and weights, I have never been convinced that the cup is as critical as pitch, since we are always going to have significant [b]slip under heavy load. As the boat is unweighted for the drive home, the cup can help the upper speeds.[/b]

Wayne, I had run that exact prop (acme 1433, and it's 14.5" counterpart, the venerable 1235) on the boat before the 2315 and 2079. 2315 was night and day better for hole shot running heavy, and the 2079 was still better than both of the taller props as well.

A small diameter prop definitely has more top end, but for pushing weight at wakeboard and surf speeds, especially at altitude, diameter matters. a lot. in my real life experience, anyhow, running at 4-5000'.

This essentially was echoed when I talked to Eric today at OJ. He told me that absolutely going to a smaller diameter would increase the RPM but to your point Shawn the size is really what gives you the push to move the weight. The resolution that we came up with is to ship the prop back to him and he's gonna take some cup out of the prop. That will add some RPM and hopefully get me to the sweet spot I am after for max power + torque in the 6.0

I went out tonight and filled the bags to full then drained the rears until the boat would plane. When enough weight was out that it would allow the boat to tip just a little and the RMP to climb to above about 3800 the "grunt in the motor" and its ability to move the boat was night and day and it planed quickly thereafter. My hope is after getting the prop worked over and adding some bow weight I may have it figured out. Fingers crossed.

Want to sell your 2419?

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