Solved-Correct prop for a Grady Explorer 246G and Suzuki DF300APX

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  • Solved-Correct prop for a Grady Explorer 246G and Suzuki DF300APX

    Just found this great site. Boat is 100 miles away. Just got new motor last weekend and don't remember what Suzuki prop was installed but I think it was a 3 15X??. Motor is mounted one hole higher than my old DF250. The boat full of fuel & ready to fish with a few people on board weighs close to 6,000lbs. I know I am turning too many RPMs for the speed I was going. The boat would not plane until almost 4,000 RPM. After researching, I think I need to try a 3 16X18.5. Does that sound about right?

  • #2
    I think you're going to have to fill in those question marks.

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    • #3
      What was your top speed with your normal load with the old 250 HP motor?

      From that, we can figure out how fast it "should" go with a 300. I'm guessing 2-4 MPH faster.

      With a DF300, an 18.5 pitch Suzuki prop is good for about a 50 MPH boat if it has low slip and you turn up a little over 6000. so depending on what your old speed was, that will tell us what pitch you will likely need.

      Ken Reeves
      [email protected]
      941-735-5808

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      • #4
        I never ran wide open much. I think the most I saw was around 38MPH @ about 5,600rpm. The boat would plane at about 3,300rpm and go about 30MPH @ 4,500rpm.

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        • #5
          Well, if you got 38 MPH at wide open with the 250, I'd expect about 42 MPH out of the 300.

          Assuming you were running a 16 X 17 prop on your old Suzuki. 4500 at 30 MPH would be 7% slip. and at 38 MPH you were probably turning 5700.
          (all just guessing)

          With the New 300 motor, you could probably run the same 16 X 17 prop, but you will likely be low on RPM.

          That is the lowest pitch Suzuki makes, so you may have to go with another brand if you can't turn a 17 pitch.

          Where is the prop that use to be on your 250 ?


          Ken Reeves
          [email protected]
          941-735-5808

          Comment


          • #6
            16 X 17 runs perfect. I found someone with the same boat & motor. BTW, my old prop was 16 X 18.5.

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            • #7
              Originally posted by white diamond View Post
              16 X 17 runs perfect. I found someone with the same boat & motor. BTW, my old prop was 16 X 18.5.
              Sounds great. The 300's are hard to setup, so could you post your performance numbers? We know you're running the Zuke prop.

              At a min, top speed, rpm and maybe how far you're trimming out.

              Thanks!

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              • #8
                I did not get time to run much and too much boat traffic to keep my eyes on the gauge. The boat planes now around 3,400 RPM. I pushed it wide open for just a couple of seconds and it easily hit 6,000 RPM but i did't look to see how fast I was going. Still seeing 30-31 MPH @ 4,500 RPM but the motor is quieter and runs with less effort than the old DF250. It almost feels like I get a turbo boost around 4,400 RPM!

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                • #9
                  Originally posted by white diamond View Post
                  I did not get time to run much and too much boat traffic to keep my eyes on the gauge. The boat planes now around 3,400 RPM. I pushed it wide open for just a couple of seconds and it easily hit 6,000 RPM but i did't look to see how fast I was going. Still seeing 30-31 MPH @ 4,500 RPM but the motor is quieter and runs with less effort than the old DF250. It almost feels like I get a turbo boost around 4,400 RPM!
                  Sounds good. When you have time and conditions, could you post back with top speed,rpm, and possibly trim. Does your Grady need bow lift to get good numbers...as the Zuke prop seems to have poor bow lift.
                  Thanks!

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