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  1. #1

    Default What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Hello all and thanks for letting me join the forum! I am rebuilding a 1980 Evinrude 25hp and I am wondering what are the main differences between a 25 and 35hp? Am I correct to understand it's the same engine block and maybe just a carburetor difference? Any information would be much appreciated!

  2. #2
    Join Date
    Apr 2010
    Posts
    4,286

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Go to a parts book and compare the two motors.

  3. #3
    Join Date
    Jun 2013
    Location
    Duluth Mn
    Posts
    658

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Look at carb, jetting, and possibly reed block.

  4. #4
    Join Date
    Jun 2013
    Location
    Duluth Mn
    Posts
    658

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Free parts manual here at marineengine.com. I use it all the time, I work on every boat motor made. Manuals on my shelf expire, this site stays current.

  5. #5
    Join Date
    Nov 2011
    Posts
    1,958

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Different lower units and props. Even if you swap carbs and all that stuff, it will not perform like a 35. Save your money.

  6. #6
    Join Date
    Jun 2013
    Location
    Duluth Mn
    Posts
    658

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    So we have a different gear ratio? Really? That motor has a host of prop choices for almost any application. I rebuild props here at my shop, got at least 4 different ones for the 35's.

  7. #7
    Join Date
    Nov 2011
    Posts
    1,958

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    I wasn't speaking of gear ratios, nor did I even think of that. I was speaking in terms of the shape of the gearcase & prop and how easily they move thru the water. I've had both types on my (same) boat and the 35 can run circles around the 25 both at top end and pulling power. And the 25 was a lot worse for ventilation. Yeah, I know, there may be other variables. Including I did not soup up the 25.

  8. #8
    Join Date
    Jun 2013
    Location
    Duluth Mn
    Posts
    658

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Yeah. I have both here in my shop. The smaller 25 lower unit may not withstand the extra 10 hp. I did modify a 25 which I run yearly alongside a 28 and now the 25 is producing maybe 30 hp. The 28 hp has the same lower unit as the 25. I used to run twin 30 Johnsons, but one of my Johnson's got stolen from the storage shed at our Ontario resort. Why is it that two 30's produce more freighting power than a single 60hp?

  9. #9
    Join Date
    Nov 2011
    Posts
    1,958

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    That's fairly typical of twins. More prop blade area. The trade-off is more drag in the water at high speed.

  10. #10

    Default Re: What are the main differences between a 1980 Evinrude 25 hp and a 35 hp?

    Thanks all for the responses. I am building a 25hp I was just wondering what the main differences are between the two. Thanks again!

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