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  1. #1
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    Z9 is SLOW. Need some help

    2012 Z9 with a matching year mercury 250 pro XS. This is my cousins boat and I'm not familiar with Nitro, need a little setup help.

    It currently has a 24 tempest that is turning around 5600 RPM. The boat maxes out around 56 mph currently. Maybe it's just a Nitro thing, but compared to my Phoenix it has basically zero bow lift. Trimmed all the way down to trimmed all the way out it barely feels like it's changing and just runs flat.

    I believe P2P is around 3" but I'll have to re-measure for him. It's also on the factory jackplate which is probably 6", could be more though.

    I know that boat should be hitting upper 60s. Hoping somebody has the same setup and can give some insight on what they're running so we can adjust accordingly and try a few things.

    Thanks

  2. Moderator Fishysam's Avatar
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    #2
    Lower the motor to 3.5" take all heavy stuff out of the front and take it back out and run it all trimmed up

  3. Member
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    #3
    25P Tempest set at 3.5" BP will likely be the best prop for that setup. The 24 might not be enough to maximize the performance of that year and hull.
    I had a 2013 and ran the 25P Tempest and saw 67 68 and could touch 70 by myself with a light load.

    You also want to make sure you are getting wide open throttle. Check the linkage to make sure it's opening all the way. 5600 rom seems a little low....I start there first.

  4. Nitro Boats Moderator BMCD's Avatar
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    #4
    almost sounds like his motor may have lost an ignition coil. ALL my previous Z9s were 68-70 running a 25p tempest. Highly suggest changing the fuel filter. Easy to do and eliminate a potential issue
    Bryan McDonough
    2023 Nitro Z21 XL
    Nitro Team

  5. Member
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    #5
    I thought about the coil thing.....but you would notice a rough running engine?

  6. Moderator Fishysam's Avatar
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    #6
    Quote Originally Posted by Flippin 416 View Post
    I thought about the coil thing.....but you would notice a rough running engine?
    COuld be idling fine but loosing power to get it lit up at the top end...

  7. Nitro Boats Moderator BMCD's Avatar
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    #7
    and the zero bow lift could be an issue too.
    Bryan McDonough
    2023 Nitro Z21 XL
    Nitro Team

  8. Member
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    #8
    Thanks for the suggestions. We’ll check some things and I’ll report back.

  9. Member
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    #9
    The hull of the boat may have a hook in it. Put a flat edge down the length of the hull to see if it’s bowed. It’s a hull defect on a lot of nitros in that year range. It creates a lot of drag.

  10. Member
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    #10
    Should be faster than that for sure, but a Z9 is pretty underpowered with a 250 on it, really needs a 300 to get the best out of it. For a 250hp stick with a Z8.

  11. Nitro Boats Moderator BMCD's Avatar
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    #11
    Not 100% sure about that above comment... it should be a 68-70mph boat.
    Last edited by BMCD; 02-06-2023 at 04:52 PM.
    Bryan McDonough
    2023 Nitro Z21 XL
    Nitro Team