Evinrude E-NATION, for those dedicated to water, power, fishing and fun
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Mate
Posts: 3
Registered: ‎05-19-2014

Prop Question/Suggestions

Hi, I'm new to the boating world and just purchased my first boat. My new boat is a Qwest 820 LS splash pad tritoon. The length of the boat is approx 21 feet. The motor is an Evinrude 150hp HO. So far I've only been able to get the RPM's up to 5000 running wide open throttle. The recommended WOT RPM range is 5300-6000. I have had the boat up to 45 mph according to my GPS on fish finder. I'm happy with the speed as I was told by the salesman that it would probably do about 43 mph. My question is should I ask about getting a different prop to get the RPM's up. When I first drove the boat I didn't trim the motor at all during WOT and it was trimmed all the way down. I could only get up to 39 MPH 4800 rpm's with the motor trimmed all the way down. The second time I ran the boat I gradually trimmed the motor up during WOT and climbed up to 45 mph at 5000 rpm's. I was able to repeat this same run multiple times with the same results. My current prop is a stainless steel, three blade, rebel. I don't know the diameter or pitch. Would the boat go even faster if I was able to increase RPM's to the upper range of the recommended motor output during WOT? Or would it just perform better as far as hole shot? I have a hard time believing this boat would go much faster than 45mph. It's probably not designed for that anyway. Thanks!
Admiral
Posts: 7,586
Registered: ‎07-14-2011

Re: Prop Question/Suggestions

5000 is too low an rpm for full throttle on your engine.

 

If you could find out the size of your Rebel prop, we could offer suggestions for better performance. My guess is that the 15" Rebel should work fairly well but if more rpm is needed, then a 15" SSP would be bring the rpms up.

 

For a pontoon boat it is better to choose a propeller that turns near the top of the rpm chart,to allow for rpm loss when you bring a large number of people on board and all their gear.

 

 

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


Mate
Posts: 3
Registered: ‎05-19-2014

Re: Prop Question/Suggestions

Thanks for your input.  I just want to make sure before I ask the dealer to bring another prop out.  I will try and find out the prop size and pitch. 

Mate
Posts: 3
Registered: ‎05-19-2014

Re: Prop Question/Suggestions

The prop is a 15 1/2 x 17.
Admiral
Posts: 7,586
Registered: ‎07-14-2011

Re: Prop Question/Suggestions

If your Rebel 17" turns about 5000 rpm, a Rebel 15" may get up to about 5400 rpm which still is not enough. Are you sure you are trimming as high as you can without letting the prop catch air and lose its grip?

 

To get some more rpms, the SSP 15" may be the way to go or possibly a Viper 15" or 16". See if you can try several props to find out which gets the rpms near the top  of the operating range plus gives good speed. Propping is trial and error most of the time.

 

the following links are test reports on a pontoon boats similar in speed to yours.

 

http://www.evinrude.com/Content/Pdf/neutral/performanceReports/PE971.pdf

 

http://www.evinrude.com/Content/Pdf/neutral/performanceReports/PE989.pdf

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.