Pontoon Prop selection

[DanDeClue]

Hey Y'all,
The wife and I just purchased a Sweetwater 220 pontoon with a Yamaha F115 engine. It came with a generic 13 1/2x15 prop. I immediately upgraded, or so I thought, to a 13 1/2x17 Ballistic SS prop. I had driven one of the Marina's rental pontoons with the Generic on it and it was okay, But I figured it would do better. The salesman, suggested the Ballistic as that was what most people went with. Okie Dokie. NOW, Three weeks in and I notice suddenly that the prop begins to slip on the hub, not allowing me to get over 3500 rpm and a top speed of around 15mph. This sucks. I removed the prop and upon looking at it I notice that the rubber on the hub is somewhat mishapen and there is what appears to be a hunk of rolled rubber on one side of it. I have attached a pic...any ideas? Thanks in advance. Dan

 

[YoungMind]

Re: Pontoon Prop selection

You possibly have a spun hub. Maybe go to the place that sold you the prop and see if they will work with you on getting it fixed. That is a pressed in hub and must be done with a press. Replacing the hub will be cheaper than replacing the prop.

To be sure it is a spun hub, get a little dot of paint or something water resistant and mark a small line on the edge of the hub and run it to the sidewall of the prop. Now put the prop back on and go run the boat for a few minutes. When you take the prop back off, if the lines don't match anymore then you have a spun hub.

 

[Maclin]

Re: Pontoon Prop selection

Regarding the pitch change, ANY pitch change needs to consider the WOT rpm's and MPH being obtained by the current setup. If the pitch was already too high, then going higher can kinda sorta overload the prop and the hub might "see" too much torque for too long a time. Pontoons are a heavy load for any prop, just sayin'.

A pontoon prop usually has larger blades and lower pitch than comparative props used with the same engine on a planing vee hull.

 

[YoungMind]

Re: Pontoon Prop selection

Regarding the pitch change, ANY pitch change needs to consider the WOT rpm's and MPH being obtained by the current setup. If the pitch was already too high, then going higher can kinda sorta overload the prop and the hub might "see" too much torque for too long a time. Pontoons are a heavy load for any prop, just sayin'.

A pontoon prop usually has larger blades and lower pitch than comparative props used with the same engine on a planing vee hull.

^+1 I had spaced that it was a pontoon. Depending on where the original prop got the rpms you may be looking for a 13 or 11 pitch.

 

[steelespike]

Re: Pontoon Prop selection

What was the wot rpm and gps speed. with the new prop. 17 does seem like too much prop.
The line across the hub and body will identify if the hub is slipping.
Typical prop applications range from 13 to 15" pitch with rpm 5850 to 6000.
Tri tunes sometimes use the same size as a twin toon but with more speed. I think the slip is lower.