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  1. #1

    Lean Runaway - 01 GP1200r

    First off I want to thank everyone on Greenhulk. Every question I've had rebuilding this ski was answered here or in the service manual. With the exception of this single question.
    I acquired a crap pair of 01 GP1200R skis. They are in desperate need of some TLC. Without prior knowledge of ski mechanics I thought I would dive in head first with help from Greenhulk.

    - rebuilt the carbs, pop-off pressure tested and all - Thanks Greenhulk for the knowledge.
    - replaced the #3 piston head and bucket. The piston head was smashed up pretty good and the bucket was broken at the bottom.
    - removed the cat-converter and installed the D-Plate and chip.
    - removed the oil pump. Installing a block off plate. I'm now running 2-cycle.
    - installed a free flow exhaust
    - installed a bilge pump

    After putting everything back together I found that I'm having a lean runaway issue.I don't have a way to completely remove the engine from the hull for a pressure test.
    So I double checked my work. Removed the carbs resealed everything again. And I'm still having the same lean runaway issue.

    Before I get into this ski for the third time I have a question.
    I do not remember installing a gasket on the oil pump block off plate. Is there any chance the air leak would come from there? If so could that cause my lean runaway issue?

    Any advice would be greatly appreciated.
    Last edited by Del Toro; 06-19-2020 at 03:06 PM.

  2. #2

    Join Date
    Jul 2019
    Buffalo, NY
    The blockoff plate needs a gasket. This leak will certainly cause your issue. You can get a Felpro gasket kit from Advance Auto and make your own...use the blue gasket material. Here's the link.....

  3. #3

    Thanks for your reply.
    I put a gasket on the oil pump block off plate. I also re-replaced the gaskets on the carburetors, cylinder #3 upper and lower and the power valve cover. There is no way any of these are leaking air.

    I put the ski in the water still on the trailer for testing today. It started and idled perfectly. But when I throttle up the engine stalls.

    Here’s my idea. When I rebuilt the carbs I put in a 2.0 needle and dull silver spring. This is different than what was there originally. I never adjusted the high and low speed jets. They are still plugged from the manufacture.

    Would this cause the throttle up stall?
    Or am I still looking at an air leak?
    Last edited by Del Toro; 06-20-2020 at 04:14 PM.

  4. #4

    Join Date
    Aug 2007
    It can still be sucking air, but if it's in the water it'll just die because it's not making enough power to spin the impeller

  5. #5

    Join Date
    Jul 2019
    Buffalo, NY
    Just wondering.... were you able to figure this out??

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