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  • Need some help with a new jetboat.

    I think I have the wrong pitched impeller in my new jetboat. I'm not getting the performance that I expected.

    I have a 24 ft Weldcraft with the 454 and a 2.4 TBO impellar. I'm only running about 24 mph at 3600 rpm, takes 4300 to get up to 29 mph. I'm thinking I need something more aggressive.

    Any one have any insight? Idealy I'd like to see if someone has a 3.4 that I could try out without having to buy one.

  • #2
    Originally posted by hntr View Post
    I think I have the wrong pitched impeller in my new jetboat. I'm not getting the performance that I expected.

    I have a 24 ft Weldcraft with the 454 and a 2.4 TBO impellar. I'm only running about 24 mph at 3600 rpm, takes 4300 to get up to 29 mph. I'm thinking I need something more aggressive.

    Any one have any insight? Idealy I'd like to see if someone has a 3.4 that I could try out without having to buy one.
    Hami 212 jet unit? What is your WOT rpm? Top speed on a lake? Need to make sure your tach is correct.

    2.4 seems a little small....I may be able to work you a deal to try my 3.4 but I am thinking you may actually want a 3.0 or 3.2 if running the motor stock and plan on heavier loads. My motor is beyond stock and rarely do I run heavy.

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    • #3
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      Yes its a Hamilton, sorry, forgot to mention that. The tach does bounce every now and then.

      Those speeds were in PWS haven't had it on a lake yet. The motor and jet is as is from factory previous owner never even had the jet apart. I just took it apart and filed down the leading edge of the impeller, I included what it looked like.

      I do plan on heavy loads of moose meat, but don't we all.

      What is a "WOT rpm"?

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      • #4
        Originally posted by hntr View Post
        [ATTACH=CONFIG]49697[/ATTACH]

        Yes its a Hamilton, sorry, forgot to mention that. The tach does bounce every now and then.

        Those speeds were in PWS haven't had it on a lake yet. The motor and jet is as is from factory previous owner never even had the jet apart. I just took it apart and filed down the leading edge of the impeller, I included what it looked like.

        I do plan on heavy loads of moose meat, but don't we all.

        What is a "WOT rpm"?
        hntr, Your impeller is in serious need of a rebuild. Filling the edges will do more harm then good at this point. Take it to AK Frontier Fabrication and talk to Garret at the new location behind Six Robblees in Wasilla on Sun Mtn View Ave. He'll be able to rebuild the impeller to better then new condition. Depending on the HP rating of your 454 you may need a 3.4 or 4.0 impeller. You could also try pitching the the 2.4 up to a 2.8 before spending money on a whole new impeller. Depending on the overall weight of the boat, you should be seeing 30mph even with a 2.4 if it's in good condition at 3600.
        North River, Alweld and Phantom Boats, Mercury Marine, FNM Marine Diesel
        Hamilton, Kodiak, Almarine Jet
        Prop, Impeller repair, Planar Heater Sales & Installation
        Visit www.akfrontierfab.com

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        • #5
          Or A-1 impellers in Anchorage
          A-1 Propeller & Impeller





          (907) 344-7767
          1220 E 68TH Ave Ste 103
          Anchorage, AK 99518
          When seconds count, the cops are just minutes away.
          '08 24' HCM Granite HD "River Dog"
          2018 12' Moto Jet "River Pup"

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          • #6
            Yes sir, that impeller looks hammered. Don't forget new wear rings to go along with the impellers.

            Comment


            • #7
              Originally posted by hntr View Post
              [ATTACH=CONFIG]49697[/ATTACH]

              What is a "WOT rpm"?
              WOT = wide open throttle. A 4.0t should only be used with a well prepped 502 or better. I know as I tried but my modded 454 wasn't enough.

              Here is the info right from Hamilton on the 212 and engines.....

              Do you make more than one Turbo?
              There are three different ones: The 2.4T is for the small block Chevrolet 350 and the Ford 351. The 3.4T was designed for Chevrolet 454 & 6.2L as well as the Ford 460. The 4T is intended for the Chevrolet 8.1 and SC 6.2L, but may also be used on some “built” Chevrolet 502. Chevrolet 6L may use the 2.4 or the 3.4.

              What kind of full throttle rpm should I expect to get with the 212 turbo?
              This will vary with the marinization and vintage of the engine, but in general, at or near sea level, we will see something close to the following rpm’s from these common engines:

              Ford 351/Chevrolet 3502.4T 4,100 - 4,200 rpm
              Chevrolet 383 “Stroker” 3.4 4,000 rpm
              Chevrolet 6L2.44,450 - 4,500 rpm
              Chevrolet 6L 3.4 3,900 - 4,100 rpm
              Ford 460/Chevrolet 454 3.4T 4,000 – 4,100 rpm
              Chevrolet 502 3.4T4,200 – 4,300 rpm
              Chevrolet 502 4 T 3,850 rpm
              Chevrolet 8.1 375 hp4 T4,020 rpm
              Chevrolet 6.2L 3.44500 rpm
              Chevrolet 6.2L 3.4T 4200 rpm
              Chevrolet 6.2L Supercharged4T 4250 - 4400rpm

              Most of the boats we see achieve an acceptable cruising speed at 2,800 to 3,300 rpm. However, this will vary widely with the individual boat and load.
              If you’re operating at higher altitude, expect to see a significant drop in rpm’s and power. You will loose roughly 3% of your horsepower for every 1,000 feet in altitude. If you’re in that situation, you may need to use a smaller impeller than you would at sea level to achieve a reasonable rpm. Be aware when running at altitude that standard gasoline engines will lose power, simply changing the impeller will only change the rpm of the jet and engine. Generally it will not make the boat go faster. If speed is required at higher altitudes consider a larger engine or even better a Turbo charged diesel or Supercharged gasoline engine.

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              • #8
                Take it to Gary at Greatland Welding in Palmer. Best place around. I agree with the others. It's looking really bad. Get it rebuilt, replace the wear ring and it will seem like a different boat.
                27' Wooldridge Super Sport Offshore Pilothouse PRIME TIME!
                Kodiak Custom Fishing Tackle Pro Staff
                Heavy Hitter Fishing Crew
                MMSI# 338232859

                Comment


                • #9
                  That impeller looks like a stone mason has been using it to cut bricks in half !!!!!!!

                  Comment


                  • #10
                    Originally posted by Big Bend View Post
                    That impeller looks like a stone mason has been using it to cut bricks in half !!!!!!!
                    The guy told me he never sucked up any rocks with it and it never even touched gravel. That's what I get for trusting people.

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                    • #11
                      Originally posted by hntr View Post
                      The guy told me he never sucked up any rocks with it and it never even touched gravel. That's what I get for trusting people.
                      I told you I sucked rocks with mine and it didn't look that bad....hope your test goes well. Enjoy that thing and thanks for cleaning mine up for me. Sorry it took so long to rip it down. I guess I should take it apart more often. Have a great time, see you when I get back.

                      Comment


                      • #12
                        Alright you guys want to see a hammered impeller and their is a claim that the boat is was able to get on step then follow this link to this forum. I knew I had seen a set that was hammered just didn't know where, but found it for you. Look close at the jig to realize how much material is missing.

                        http://www.nzjetboating.com/yabbse/i...?topic=17565.0

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                        • #13
                          hntr
                          figured out why my impeller was so hard to remove, seems I have a burr on the shaft, will have to clean up before the reinstall. I am now going to make it at least an annual requirement to pull my jet apart. I hate having to heat and beat to get things apart. Hope that thing is now flying for you.

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                          • #14
                            Just got back, took it to the lake to try it out. Wide open it turned at 4100 rpm and got 39 to 40. Cruise at 3700 got 30 mph and 3400 got 25 mph. It definitely got out of the hole much faster. Can't thank you enough for volunteering to help a new guy. And to tear down your jet and pull your impeller to do so. A real class act!

                            And I couldn't even get that impeller on until I sanded some burs down on the inside.

                            Thanks again

                            Comment


                            • #15
                              I also use plenty of anti-seize when putting it all back together.
                              "I'd rather be fishing!"

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