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    2556 happy RPMs

    Been using the boat tons and loving it!!!!!! She seems to get on plane and cruise happy at 3500 RPM. She doesn't sound overwhelmed or like she is labor it too hard.. I know in my truck at 3500 it sound kinda wound out. What is the "happy RPM" for cruising on plane.? And how long should I be running at the upper RPM range? In good conditions my wife and I could sit up on the fly bridge and run all day long if we could!
    Santa Cruz CA
    1981 3270
    1991 2556

    #2
    My ideal cruise rpm is 3600-3800. I’ve run 3 hours straight at that rpm and could likely double that if needed. Talk nice to her and she’ll treat you good😉
    Dave
    Edmonds, WA
    "THE FIX"
    '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
    (.030 over-Vortec top end-part closed cooled)
    The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
    Misc. projects thread
    https://www.baylinerownersclub.org/f...56-gctid789773

    Comment


      #3
      Originally posted by seanV18 View Post
      Been using the boat tons and loving it!!!!!! She seems to get on plane and cruise happy at 3500 RPM. She doesn't sound overwhelmed or like she is labor it too hard.. I know in my truck at 3500 it sound kinda wound out. What is the "happy RPM" for cruising on plane.? And how long should I be running at the upper RPM range? In good conditions my wife and I could sit up on the fly bridge and run all day long if we could!
      Great questions.

      Cruising RPM will be determined by several factors.
      First..... perform your WOT RPM test! This is an RPM that the engine should be able to achieve at the Wide Open Throttle position.


      NOTE: WOT RPM is a test RPM ONLY..... and is NOT an RPM that is to be sustained for any duration, unless you wish to shorten the life of your engine(s).

      Requirements for the WOT RPM test:
      .... engine in good health and in full tune.
      .... hull clean.
      .... prop in excellent condition.
      .... correct over-all gear reduction.
      .... boat loaded as you would normally load it.

      The engine should be able to reach the OEM specified WOT RPM range.
      (it's better to be in the higher side of the range, than to be in the lower side of the range)

      Planing out with a gasoline V-8 engine:
      .... the hull should come up and get onto "step" and then just a tad bit more. ( the "tad bit more" ensures that the hull is planing out correctly, and it reduces hull friction and engine load)
      .... engine speed will likely be in the 3,600 to 3,800 RPM range.
      .... engine should easily achieve the WOT test RPM range .


      As for the; "how long should I be running at the upper RPM range?".... if this hull planes out (with the tad-bit-more) at between 3,600/3,800 RPM, the limitations will be:

      ..... engine over-heating issues.
      ..... oil pressure issues.
      ..... fuel capacity, while paying close attention to the 1/3 out, 1/3 back and 1/3 general reserve rule.

      Otherwise, you should be able to run a long duration at that speed.






      Rick E. Gresham, Oregon
      2850 Bounty Sedan Flybridge model
      Twin 280 HP 5.7's w/ Closed Cooling
      Volvo Penta DuoProp Drives
      Kohler 4 CZ Gen Set

      Comment


        #4
        Originally posted by seanV18 View Post
        Been using the boat tons and loving it!!!!!! She seems to get on plane and cruise happy at 3500 RPM. She doesn't sound overwhelmed or like she is labor it too hard.. I know in my truck at 3500 it sound kinda wound out. What is the "happy RPM" for cruising on plane.? And how long should I be running at the upper RPM range? In good conditions my wife and I could sit up on the fly bridge and run all day long if we could!
        What engine/drive are you running?

        Comment


          #5
          Thanks guys. Great information!

          Im running a mercruiser 5.7 with a Bravo 1 gen 1 OD. Thinking I may be spot on keeping her at 3500 and sneaking up to an occasional 3800. Hoping to find the balance between speed,fuel economy and engine longevity.

          And I always talk nice to her. My wife tells me too all the time!
          Santa Cruz CA
          1981 3270
          1991 2556

          Comment


          • Nauti_Mike
            Nauti_Mike commented
            Editing a comment
            A Bravo 1 on this size boat. I would think it either had a Bravo 2 or Alpha 1Gen 2.

            Bravo 1 is typically used on performance style boats.

          #6
          Sorry, you are correct. Alpha 1. Thanks for the correction.
          Santa Cruz CA
          1981 3270
          1991 2556

          Comment


            #7
            Originally posted by seanV18 View Post
            Sorry, you are correct. Alpha 1. Thanks for the correction.
            Sean, I may have asked this before but what kind of speed do you see at your 3500 rpm?
            What prop diameter and pitch?
            What is the overall drive gear ratio?
            Dave
            Edmonds, WA
            "THE FIX"
            '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
            (.030 over-Vortec top end-part closed cooled)
            The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
            Misc. projects thread
            https://www.baylinerownersclub.org/f...56-gctid789773

            Comment


              #8
              I have just hooked up my electronics and have not read the speed on plane yet. I should be going out Friday and will check then. And sorry but don't know the prop info or gear ratio. Wish I did. Will chime back in with speed once confirmed.
              Santa Cruz CA
              1981 3270
              1991 2556

              Comment


                #9
                Originally posted by seanV18 View Post
                I have just hooked up my electronics and have not read the speed on plane yet. I should be going out Friday and will check then. And sorry but don't know the prop info or gear ratio. Wish I did. Will chime back in with speed once confirmed.

                That would be good information to have in your log book.
                Rick E. Gresham, Oregon
                2850 Bounty Sedan Flybridge model
                Twin 280 HP 5.7's w/ Closed Cooling
                Volvo Penta DuoProp Drives
                Kohler 4 CZ Gen Set

                Comment


                • builderdude
                  builderdude commented
                  Editing a comment
                  And for other future 2556 owners running the Alpha drive.
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