Prop help

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  • Prop help

    I own a 23cc Tidewater with a 4.2 Yamaha running a 15.5 X 17 Saltwater series II prop but max rpm are only 5300 any suggestions to reach max rpm around 5900?

  • #2
    Until Ken2 comes along, I'll give you my advice from owning a similar hull and motor. I tried the 17 SWS and also got about the same rpm as you.. The prop blades are just too big. The 17" Reliance series is a much better fit. When trimmed it gets up to about 5800. I also tried a 19" Michigan Wheel and it didn't do much for me and I tried the 21" Reliance which surprisingly worked fairly well with a light load but dogged out when loaded.

    Currently I have a Reliance 18" x (I think) 14 1/4" which runs just a touch faster than the reliance 17". Maybe 1 or 2 mph faster. For now, I'm sticking with that one.

    BTW, it's on a 200 HPDI and it came with the Reliance 17".

    Comment


    • #3
      What HP is your motor?
      I see the yamaha reports. F250 ran 51 mph with a 17 sws. https://yamahaoutboards.com/en-us/ho...2016-08-07_occ
      F300 ran 51 also, but maybe its a little differnet model. https://yamahaoutboards.com/en-us/ho...2017-08-03_occ

      Looks like both had the motors mounted in #3, which is almost as high as it will go. #4 being the highest.

      What GPS speed are you getting at 5300 RPM?
      Are you trimming the motor up much at wide open?
      what happens if you trim higher?
      How much Fuel, gear, people do you have on the boat for your 5300 wide open?


      The general answer to your question would be to drop down to a 15 pitch to get your RPM up.
      But would be better to know what your actual numbers are and what its doing.

      Ken Reeves
      [email protected]
      941-735-5808

      Comment


      • #4
        2017motor and boat 250HP, 3rd hole, 43mph reading with Yamaha digital gauge, trimmed up 2 to 3 people no more than 75 gallons of gas 100 to150lbs. of gear. Thanks Ken

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        • #5
          One more thing I'd check before changing props is your GPH at wide open.
          Should be burning right around 24 GPH. if your burning less, maybe the throttle position is not set correctly
          A bunch of guys posting their numbersd on the tidewater site.
          https://www.tidewaterowners.com/your...ight-t227.html
          Most seem to be running high 40's, low 50's.

          Ken Reeves
          [email protected]
          941-735-5808

          Comment


          • #6
            I thought of the throttle position but do not know how to adjust that?Any clue on adjusting.Thanks again Ken

            Comment


            • #7
              Well, you can just see what your GPH is at wide open. that will tell you if your getting it or not.
              23-24 GPH your getting full throttle on a 4.2L yamaha 250

              I don't know if you have fly by wire, or cables. SHO or Offshore


              Ken Reeves
              [email protected]
              941-735-5808

              Comment


              • #8
                I have cables and offshore model.

                Comment


                • #9
                  Parker Yacht on SIM on here could probably help you with the adjusting if you find your fuel burn is not what it should be at wide open.

                  Ken Reeves
                  [email protected]
                  941-735-5808

                  Comment


                  • #10
                    Thanks for your help will do.

                    Comment


                    • #11
                      What is the pitch on a 15M yamaha prop

                      Comment


                      • #12
                        15 pitch.
                        yamaha makes the reliance, saltwater series, and painted stainless.
                        Just make sure you know which one your looking at.

                        Ken Reeves
                        [email protected]
                        941-735-5808

                        Comment


                        • #13
                          it is a stainless prop with no name except 15M on it and is it a 15inch diameter prop

                          Comment


                          • #14
                            Got a picture of it? does it say 15 inch diameter on it? or you just measured it?

                            Yamaha has the
                            Painted Stainless that is 15 1/4 X 15
                            Saltwater Series that is 15 3/4 x 15
                            Reliance which is 14.5 X 15


                            Ken Reeves
                            [email protected]
                            941-735-5808

                            Comment


                            • #15
                              I'm not sure if we've talked on the Facebook page or on the Tidewater owners site? Asking about a 15P makes me think we may have. Ken is asking about your fuel burn as something else is going on if you are only turning 5300 with the 17P and in hole 3 from the bottom. It could be that your throttle isn't set right to let you get the whole way out to 6100 RPM or close to that. I can hit WOT no problem at all with my 250 SHO and 2016 230 and 17P. I think I hit it loaded down with 4 guys, full tank of gas and a bunch of gear.

                              In fact, I've talked to Ken a few times about trying an 18P Eco or similar so I'm not hitting the limiter.

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