Evinrude E-NATION, for those dedicated to water, power, fishing and fun
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Mate
Posts: 2
Registered: ‎03-15-2012

Help with prop. What else?

I wanted to do as much testing on my own as I could before I came in here to solicit additional advice.

ENGINE: E-TECH

HP: 250

YEAR:2006

BOAT: Boston Whaler

TYPE: CC Outrage

SIZE:22 ft.

FUEL:60 Gallons

WATER:10 Gallons

LOAD:Half tank of fuel

OCCUPANTS:1

GEAR: Normal fishing gear

SPEED UNITS:In Statute miles

SPEED OBTAINED: By GPS

CONDITIONS: Calm seas, No wind

 

 

Here are the results I got using a variety of props available from my dealer for testing. Based on these numbers I thought I would try a Viper 14 3/4 X 20 which I haven't yet. What would the experts recommend?

 

I will try to post the spread sheet format I used to keep track of the data. If my attachment does not work, I may have to re-post this again, this time typing out everything in a table format. Thanks for any help you can provide. I am pen to all suggestions including props by manufacturers other than the ones I tested..

 

PROPVIPERREBELGENERICVIPERREBELCYCLONE
STYLE3 BLADE-SS3 BLADE SSALUMINIUM3 BLADE SS3 BLADE SS4 BLADE SS
SIZE14 3/4  X  1915 1/4  X 1914 1/4 X 2114 1/2 x 2115 3/8 X 18141/8 x 19
PART NUMBER763918763990391202763922763988763942
       
TIME TO PLANE8 secs.6 secs.11 secs.6 secs.4 secs.5 secs.
MIN.PLANE RPM310030002950300030002900
MIN.PLANE   SPEED22.022.021.923.623.121.1
TRIM0%0%0%0%0%0%
       
4000 RPM      
SPEED33.535.835.437.035.836.2
GPH10.612.312.112.211.511.8
TRIM14%20%38%40%55%55%
       
4500 RPM      
SPEED38.240.23943.340.341.1
GPH12.615.615.315.914.515.5
TRIM18%20%38%45%45%45%
       
WOT 575051505500515056005200
SPEED50.147.248.448.649.748.6
GPH22.521.122.821.022.822.0
TRIM25%37%60%45%50%45%

 

 

Admiral
Posts: 8,432
Registered: ‎07-14-2011

Re: Help with prop. What else?

 

 

Your engine has a red-line of 5800 rpm and the factory literature recommends an optimum rpm range of about 5500 to 5600 rpm for all around performance and economy.

 

As you can see, the Rebel 18 is a good match for everyday use and mid-range economy. The 20" Viper may be a good choice also, but historically the Viper is great for top speed but is not the most efficient at cruising speeds and acceleration.

 

For checking fuel economy, don't rely on rpms, use constant speeds such as 30mph, 35mph, or 40mph then record the fuel consumption for each propeller. That way you can figure miles per gallon to compare prop efficiencies at cruise, where you will spend much of your boating time.

 

 

 


"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: 2
Registered: ‎03-15-2012

Re: Help with prop. What else?

Bill,

Was it 5800 RPM limit on 2006 models also?

 

So if the prop I settle on is revving 5850, it is the wrong prop. Is the 5800 -Never exceed- RPM?

The reason I ask, is I am expecting  with proper trim I could get the prop to turn 5850 and that would be a no no. Correct?

 

 

The printed form dealer provided me with had RPM readings as a measuring stick rather than GPS speeds. It makes sense to use the speed to measre consumption etc regardless of the RPMS.

Admiral
Posts: 8,432
Registered: ‎07-14-2011

Re: Help with prop. What else?

A top rpm of 5850 should not be a problem if it is with a light load aboard, such as one person and little fuel in the tank. If the boat was tested in cool weather, the rpm will be less on a humid summer day, especially with a full tank of fuel, bunches of people, and lots of 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.