Evinrude E-NATION, for those dedicated to water, power, fishing and fun
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Skipper
Posts: 5
Registered: ‎05-06-2015

Prop selection for '82 Evinrude 60 hp

Hi, folks!  I recently bought a 1979 Alumacraft MV pro.  It has a 1982 Evinrude 60 horse with an aluminum prop that could stand to be replaced.  I'm planning to go stainless for the replacement for it's durability, and hopefully a slight performance increase.  Two main questions...

 

1. I can't tell what the original prop is!  It says "12-1/4 X 15", or maybe "X 17".  It appears the 7 was punched in over the 5.  See attached pic.  I did find a site today that walks you through a simple prop pitch measurement, and I'll try that tonight...

IMG_0492 (600x800).jpg

2. Regardless of what the original prop is, should I match that with a stainless prop?  Or in switching to a stainless prop, should I step up (or down) the diameter or pitch a little?

 

Thanks for any help you can provide!

Highlighted
Admiral
Posts: 9,047
Registered: ‎07-14-2011

Re: Prop selection for '82 Evinrude 60 hp

[ Edited ]

 

 

Your picture shows that it was a 17" prop had its blades reformed (repitched) to be the equivalent of a 15" pitch propeller.

 

As long as your rpms are in the 5000 to 5500 rpm range at full speed with an average load, a 15" stainless prop should be OK.

 

 

 


"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.


Highlighted
Skipper
Posts: 5
Registered: ‎05-06-2015

Re: Prop selection for '82 Evinrude 60 hp

Thanks, Bill.  How do you know that it was a 17 re-pitched to 15 (and not the other way around)?

I'm not getting those RPMs at WOT.  I'm getting only a little over 4000.  I put in new plugs, and speed went from about 34 to 35 mph, but no appreciable increase in RPMs.  I'm thinking I need a 13" pitch prop...  or perhaps even less.

Highlighted
Admiral
Posts: 9,047
Registered: ‎07-14-2011

Re: Prop selection for '82 Evinrude 60 hp

[ Edited ]

I guess that I assumed that the prop was repitched lower as that is the most common reason. Your comment made me research the propeller history and you were right, it was originally a 15" pitch as that is the only size prop that has a 12-1/4" diameter. The 17" pitch prop has a 12" diameter.

 

Find a 15" or 13" prop and check the rpms. My guess is that a 15" will only give you about 4400 rpm or so.

 

What length and weight is the boat and what kind of speed are you getting?  GPS speed preferred. Also check the back of the tachometer to be sure it is set to #5, not #6 so the rpm is correct. If it was on #6, then it would read too low for your motor.

 

If it was on #6, switch to #5 and run the boat again and note the rpms.

 

 

 


"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.


Highlighted
Skipper
Posts: 5
Registered: ‎05-06-2015

Re: Prop selection for '82 Evinrude 60 hp

Hmmm... I'll have to check the tach.  I'm getting 34-35 mph measured via GPS.  It's a 16' Alumacraft MV pro... essentially an aluminum jon boat with a v-front and a bass-boat style interior: side console with 2 seats, livewell between, casting deck fore and aft with pedestal seats.

thanks, john

Highlighted
Admiral
Posts: 9,047
Registered: ‎07-14-2011

Re: Prop selection for '82 Evinrude 60 hp

 

 

Tachometers are not the most accurate of instruments but if the switch is on #6 instead of #5 on your motor, it would read nearly 16% off.

 

 

 

 

 


"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.


Highlighted
Skipper
Posts: 5
Registered: ‎05-06-2015

Re: Prop selection for '82 Evinrude 60 hp

Okay.  I pulled the Tach.  It's an Airguide, and according to the back of it, it's a "3HB".  I don't see any model numbers on it anywhere, and I don't see any switches or any way of adjusting it.

Thoughts?

IMG_0520.JPGIMG_0521.JPG

Highlighted
Skipper
Posts: 5
Registered: ‎05-06-2015

Re: Prop selection for '82 Evinrude 60 hp

Those two holes in the case don't appear to have anything in them.  I pulled out one of the screws from the back, and it seems to have dropped a nut inside the tachometer.  And I can't get the rest of it apart!  I might be in the market for a new tachometer...

Highlighted
Admiral
Posts: 9,047
Registered: ‎07-14-2011

Re: Prop selection for '82 Evinrude 60 hp

Without a setting switch on the back side, I doubt it was ever the correct tach for your motor. Get an Evinrude tach or at least one with a 270° sweep of the needle.

 

 

 


"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.