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  1. #21

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    Pop Off Too Low on Stock 1200 PV (66V)?

    I thought the low speed adjuster was for idle only? I'm kind of surprised you recommend the stock 87.5 pilot jet (GP1200R comes with 95), and also recommend the 115 gram spring. That keeps pop off high. Combination of that, to me seems like it would keep the motors lean in the lower range. Am I missing something?

  2. #22
    Tool Bag water worx's Avatar
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    Quote Originally Posted by Robb235 View Post
    Am I missing something?
    Not trying to be rude but yes you are missing the whole ideal of jetting & are way over thinking this issue.

    I am done I have told you how to fix your boat now do it or continuine to make up your own jetting that hasnt worked yet....


  3. #23

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    Pop Off Too Low on Stock 1200 PV (66V)?

    Quote Originally Posted by water worx View Post
    Not trying to be rude but yes you are missing the whole ideal of jetting & are way over thinking this issue.

    I am done I have told you how to fix your boat now do it or continuine to make up your own jetting that hasnt worked yet....
    Not trying to argue, just trying to understand. No need to get upset...

    It's just you made the statement that these boats run lean in stock form in the low speed, yet recommended the stock jet and the stock spring: the two things that control low speed fueling.

    The SBN manual states that the low speed adjuster is only for adjusting idle mixture. So that's why I'm trying to understand the "why" of what you're telling me. Click image for larger version. 

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  4. #24

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    Look at the diagram on page 7: http://www.mikuni.com/pdf/sbn_manual.pdf

    The low speed jet and needle bypass are always providing fuel especially at idle and low loads which is when the throttle plate is creating a vacuum low-pressure-area at the low speed ports dumping into the intake tract.

  5. #25
    Tool Bag water worx's Avatar
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    Do what I said & your boat will run fine.

  6. #26

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    Quote Originally Posted by water worx View Post
    Do what I said & your boat will run fine.
    Will do. Waiting on new 115 gram springs to arrive (should be tomorrow), and I'll try it out. Bad part about two motors is I'll have to do it twice lol.

  7. #27
    Tool Bag water worx's Avatar
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    Yep but in the end it will be worth it.

    Good thing is the pipes dont have to be removed unlike the jetskis.

  8. #28
    Tool Bag water worx's Avatar
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    Any update ?

  9. #29

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    Pop Off Too Low on Stock 1200 PV (66V)?

    Sorry, staining my deck took top priority this weekend. Finally had enough days in a row without rain that we could pressure wash, let dry, and stain.

    I got the carbs back together today. Both motors start without choke and idle fine. What bothers me is the "115 gram" springs I received look exactly like the shiny silver springs in my Mikuni rebuild kits. The packaging also doesn't say "Mikuni" but rather WPS. They all pop off at 40psi (1.2 N&S). I figured my Mikuni pop off pump/gauge must not be reading right. But in the water, both motors feel like they're loading up. Throttle response is not crisp. I have to pump the throttle a little bit before the motors rev freely into the higher RPMs.

    So I think my Mikuni gauge is right, and pop off is too low, causing it to load up at idle.
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  10. #30
    Tool Bag water worx's Avatar
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    I think your accel pump is not working... You have to "pump" the throttles because its not squirting the fuel.

    WPS is just a supplier for Mikuni parts. The old 115 springs were gold & the new are silver.

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