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  1. #1
    MR MAC's Avatar
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    2008 sho loosing rpm and running lean

    Hi my tuned sho is loosing rpm at extended speed runs... It hits peak rpm at 8750 then after 10 seconds power dies and it drops down to 7000 acceleration is amazing but power is dropping as described. I first thought the plugs were shot so I pulled them out and they was but were white and showing signs of being lean.

    Now since being tuned its always run fine but always has stock fuel pump. Would the fuel pump be giving me this issue?

    Thanks

    Ian


  2. #2

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    You need a fuel pressure regulator, vented hull.......I would guess that u are starving for air, fuel, and ur heat soaked. Just a guess tho

  3. #3

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    " peak of 8750 rpms" needs more prop pitch you are hitting the revlimiter very hard causing it to go all the way to the second level of over rev protection which cuts the spark to two cylinders I supect! Tommy Jordan

  4. #4
    MR MAC's Avatar
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    Thanks for the replies. Its always been OK in the past with correct AFR results and just sitting slightly below the limiter. In fact its always run a little rich at 4-6k rpm.

    Its only past two times I have gone out it has been having the problem

    Ian

  5. #5
    MR MAC's Avatar
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    As its just been the past 2 times and its done 150 hours with this set up doing 80mph+ and just below the limiter I believe something has failed.

    As all the plugs were equal I don't suspect a injector

    Ian

  6. #6
    fx160's Avatar
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    maybe there is a fuel blockage

  7. #7

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    When is the last time you changed ur plugs?

  8. #8
    formerly Gold06RXP Turbo Nick's Avatar
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    You need an AFR gauge to see where AFR is. Don't assume anything by looking at plugs. Get confirmation with accurate gauge.

  9. #9
    MR MAC's Avatar
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    Plugs were changed 5 hours before showing lean and changed 2 days ago as i thought they may be the issue.. i do have a afr gauge that i used in the past when testing and tuning the ski and all AFR readings were fine... its only past couple of times I've had the issue and the ski has been set up and tuned for over 3 years with no issue so something is failing


    ian

  10. #10
    MR MAC's Avatar
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    Also the ski takes 5-10 times starting it as it stalls but if locked and unlocked it will start fine

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