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  • X7 Advice and Info

    Hi Team Talkers. I am new and a Brit.

    ] I have just purchased an X7 with 350 MCX 1.1 with 81hours and have some questions that I am sure the "experts" can answer.
    Question 1:
    The boat is a 2005 model and is fitted, in accordance with the Owners manual, the 12.5 x 12 4 blade propellor. It runs at max revs of 5100+ and according to the Perfect Pass speedo hits 40 mph but no more. According to the 2005 manual the prop is correct for all the Evo hulls 190/197 and X7

    However, a friend has the 2004 Sammy Duvall 190 (Same Evo hull) same MCX 350 and 1.1 but according to his owners manual the 190/197 and X7 all have a 13 X 13 prop. He has the 13" prop and his boat hits about 48 mph.

    Can anyone tell me why the Evo prop specification has changed between 2004 and 2005 and what are the benefits/downside of the revised Mastercraft spec.(I have asked Mastercraft UK and not got an explanation) Also the options for increasing "my" top speed. My boat is used for Slalom, Barefooting and Wakeboard.

    Question 2: On a "hit it" there is an annoying momentory pause before the boat accelerates causing us problems on mono beach/jetty starts. Can anyone advise?

    Regards and looking for helpful answers. Ian
    Last edited by eurosysytem0; 08-10-2010, 08:30 AM.

  • #2
    eurosysytem0,
    Congrats on the new boat and welcome to the board.

    Question 1: The difference is that the older boats had cast propellers and the new boats have CNC machined propellers. A CNC prop and a cast prop are not directly interchangeable even if the are list as having the same pitch and diameter. In fact there are two prop manufacturers that most people use, ACME and OJ and their props are not directly interchangeable based on pitch and diameter.

    Have you calibrated your speedometers with a GPS? That would be my first step so you are sure exactly how fast the boat really is going. Next if the speed still isn't where you want it you might want to try getting a new prop. It might be that there is some slight damage to your current prop and that is causing a decrease in speed. Based on your current Wide Open Throttle RPMs it looks like you have the correct sized prop for your boat. The WOT RPMs for your boat should be 4600-5200 according to the Indmar manual.

    Question 2: I have had the 2003 version of your boat and I never noticed any hesitation on acceleration.

    Andyg
    Last edited by Andyg; 08-10-2010, 08:53 AM.

    Comment


    • #3
      The momentary pause might be a result of your 2005 being drive by wire. To me, they have always felt like they offered less feedback on the hole shot than the older wired boats. They lock in on speed much more quickly, but it's hard to tell how much juice you're giving your rider out of the hole.

      Is that similar to what you're seeing? In other words, you move the throttle forward expecting to feel some response from the propeller, but you don't. Then, suddenly, it kicks in and you, instinctively have kept pushing it forward while waiting for it to hit. By the time it does, you're pretty far advanced on the stick and have to adjust. Is that close?
      Previous: 1993 Prostar 205

      Red 1998 Ski Nautique, PCM GT40, 310 hp, , Acme 4 blade, Perfect Pass SG/Zbox.

      FAQ


      Be kind. Have fun.

      Comment


      • #4
        East tx skier,
        Many thanks. The concensus seems to be the move from cast to CNC on prop change- including input from Tech guys at mastercraft. I think checking the speedo is definitely the next check.

        On the pause I need to do more checks because it is a definite pause and the jump- it then goes like a bat out of hell!

        My three girls are finding it a bit of a handful when they jetty start and we all need to get used to driving the new boat. Again many thanks.
        regards
        Ian

        Comment


        • #5
          Andy G
          Many thanks. The concensus seems to be the move from cast to CNC on prop change- including input from Tech guys at mastercraft. I think checking the speedo is definitely the next check.

          On the pause I need to do more checks because it is a definite pause and the jump- it then goes like a bat out of hell!

          My three girls are finding it a bit of a handful when they jetty start and we all need to get used to driving the new boat. Again many thanks.
          regards
          Ian

          Comment

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