Moved motor from ski boat to pontoon what prop should i change to???

[danemaker]

I just switched my yamaha 90 from a 16' ski boat to my 18' pontoon. Now at wot I only get 3500 rpm and 20 mph. The prop on the motor is solas 3411-135. Im very unsure of the correct prop to replace with. Any help is greatly appreciated

 

[Scott06]

Not sure what the recommended wot rpm of your engine is. Would assume 5500

Or so I think based on the fact your current prop is a 15” pitch you need like a 9” pitch, which is really low. You may need a different gear case to push a pontoon as based of the numbers given I don’t think you can get a pitch low enough …

 

[danemaker]

Yikes gear case is way out of my price range. I dont really need optimal performance just the best i can get on a budget.

 

[jimmbo]

Keeping the Engine from dying a horrible Twitching Death is why it needs to be running in the correct rpm range. What rpms were you getting when it was on the 16ft?

 

[danemaker]

Keeping the Engine from dying a horrible Twitching Death is why it needs to be running in the correct rpm range. What rpms were you getting when it was on the 16ft?

I couldnt keep the boat from jumping to run wot. but I could easily hit 5000 rpms

 

[danemaker]

I couldnt keep the boat from jumping to run wot. but I could easily hit 5000 rpms

 

[flashback]

Solas makes a 9 so you may be in luck!

 

[flashback]

Don't use it as is, very harmful to the motor, extreme lugging.

 

[Scott06]

Solas makes a 9 so you may be in luck!

Might work but I would think a 9 would raise it 1200 rpm or so vs current 15” … still too low and lugging

 

[flashback]

Might work but I would think a 9 would raise it 1200 rpm or so vs current 15” … still too low and lugging

I agree. He needs to find a prop shop that will work with him.. I have one, I pay a fair price but he lets me exchange if needed.