** NO pop-off pressure on my 1993 Waverunner **
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  1. #1
    PWCToday Newbie
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    ** NO pop-off pressure on my 1993 Waverunner **

    Hello forum,


    we a yamaha waverunner 700 WBX from 1993.
    Carburetor (Mikuni 44mm) has been rebuilt now twice but still is giving us problems.


    Hard start (we now switched to primer which helped a bit), and after a 10min run or so it does not start at all anymore.
    When I am back at home from the boat launch it usually starts again.


    Sounds all like a possible needle and seat problem.


    So I got a new set of needle and seat from SBT, this Yamaha has a 1.5 seat.
    I also bought a pop off pressure pump to test the pop up pressure and another rebuilt kit to have it all "perfect".


    Unfortunately after many many tries ... there is no pop up at all, the N/S is not holding any pressure.
    Its hard to say but the gauge never goes over 2-3 psi, so basically nothing.

    Double and triple inspected the N/S, switched out spring and arm.




    If someone has an idea what to check or what I might be doing wrong ... very much appreciated.


    Thanks
    .axel

  2. #2
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    sorry, I forgot to mention that I sprayed WD40 to keep the needle wet, I followed the detailed pop-off video from SBT

  3. #3
    PWCToday Newbie YamasakiFord's Avatar
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    I'll ask the obvious.. But do you have the return blocked off?

  4. #4
    PWCToday.com Is My Home Away From Home Myself's Avatar
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    +1 on the return
    http://www.facebook.com/twinlakesjetskirepair

    '89 Kawi 650SX 42.4 GPS
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  5. #5
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    I made a video of me pressure testing.
    Maybe someone can tell me what I am doing wrong.

    Thanks!



  6. #6
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    I am new to this as well but I had the same issue with a gauge I got off amazon - the valve that is for the pressure release on the gauge wasn't sealing so I wasn't able to build any pressure. You can test by just putting your finger on that clear tube or capping that one and seeing if the gauge holds pressure. Mine didn't and had to send it back and ordered a Mikuni gauge and worked fine off the carbs (Ill be starting my rebuild this week). Long shot but thought I might through it out there. Best of luck

  7. #7
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    I have tried putting my finger on the end of the clear tube ... it holds pressure and shows it on the gauge, can get it up to 10psi

  8. #8
    PWCToday.com Is My Home Away From Home john zigler's Avatar
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    Bad needle and seat.... That or installed incorrectly... (I have seen many times, the needle arm/spring not seated correctly)

    Did you use genuine Mikuni brand needle and seat, and kit when you rebuilt?
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    608-743-1305 9am to 5pm CST m-f
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    new parts / products / services www.watcon.com
    thank you

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  9. #9
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    Quote Originally Posted by john zigler View Post
    Bad needle and seat.... That or installed incorrectly...
    really, well I will triple check needle and seat then. I never had the seat out, just the needle.

    I used the shop hose just to check if the actual mecanism is working ... seems ok to me. So why would needle and seat not be ok? Any help very much appreciated.


    Here is me trying it with the shop hose.



  10. #10
    PWCToday Newbie
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    Re: ** NO pop-off pressure on my 1993 Waverunner **

    After playing more for a while, it was the gasket of the seat.
    Its old, bad and brital ...

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