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Thread: gp1200 rebuild

  1. #1

    gp1200 rebuild

    Hi guys have just rebuilt my gp 1200 and iamhaving troubles when ever i power out of a sharpturn the ski just dies , mods that i have done are not that much and are following
    1 mil overe size bore
    vertex pistons
    carbon tech reeds
    carby kit, removed choke plates
    primer kit
    solas 13/19 impeller
    the head got a little shim as well
    and run it premix 50:1
    nothing over bored just a basic rebuild , have tried a new fuelfilter but stillno better, once the ski gets up she flies just sharp turns make it run real rough


  2. #2
    Mpeavler's Avatar
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    restrict your fuel return line with an inline restrictor that Jerry sells here on the boards. You maybe loosing to much fuel out the rail under hard "G" forces

    M

  3. #3
    i tried clamping the return line and it made no difference i also clamped the lines to the primer kit as well, i installed my prime kit on the return line

  4. #4
    Mpeavler's Avatar
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    I would go through the carbs. Take then apart and LOL for gunk, dirt etc.
    Spraying the throats won't do anything for you.

  5. #5
    jdog800's Avatar
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    Check your ground. I have seen this happin before where the ski looses ground during a sharp turn and kills the motor.

    Another issue that can cause this is metal flakes inside the flywheel cover touching one of the pickups. Over time the flywheel rubs little flakes of metal off of the starter bendix. These flakes can ride on top of one of the pickups and when you turn sharply short out the spark. You will have to remove the cover to the flywheel and may also have to remove the flywheel itself if there is alot of buildup.
    I would try the ground first though much easyer.

  6. #6
    Mpeavler's Avatar
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    Quote Originally Posted by jdog800 View Post
    Check your ground. I have seen this happin before where the ski looses ground during a sharp turn and kills the motor.

    Another issue that can cause this is metal flakes inside the flywheel cover touching one of the pickups. Over time the flywheel rubs little flakes of metal off of the starter bendix. These flakes can ride on top of one of the pickups and when you turn sharply short out the spark. You will have to remove the cover to the flywheel and may also have to remove the flywheel itself if there is alot of buildup.
    I would try the ground first though much easyer.
    good points J

  7. #7
    so by the ground, you mean check where the black thick cable connects to the engine block near the starter motor, the carbs should be good as i had a mechanic do them for me, will modifying the hi and low speed jets have alot of effect, can anyone sugest what settings i should run with the chokes removed and the new reeds, or will the settings in the owners manual be good enough???

  8. #8
    jdog800's Avatar
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    I believe removing the chokes and reeds calls for one size rejet.
    Try opening the low speed to 1 1\4 turns out and the high to 1 turn out, and see how it runs. If it falls on its face when takeing off open up the lows a little more.
    If this fixes your problems then you have jetting issues. If it doesnt look else where.


    and yes the ground is the black wire going from the battery to the motor......it comes loose sometimes.

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