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  1. #1
    Cadet
    Join Date
    Aug 2009
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    Plymouth,Michigan
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    4

    Default Rochester 2 bbl carb has no idle speed screw

    I have a rochester 2 barrell carburator 2 jet style on my GM straight 6 cylin engine.I have come to the conclusion that the idle speed screw does not exist on this model.Is it possible that you simply use the two idle mixture screws to adjust the idle?I have a merc 165 stern drive if that matter's.

  2. #2
    Commander 45Auto's Avatar
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    May 2002
    Location
    Slidell, LA
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    2,826

    Default Re: Rochester 2 bbl carb has no idle speed screw

    Should be right at the base of the butterfly shaft unless someone has "worked" on it in the past .....

    From Mercruiser Manual #3, 1978-1984 Engines - 4,L6,V8:

    Any opinions expressed above are worth exactly what you paid for them!

  3. #3
    Captain
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    Mar 2009
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    Central CAL
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    3,560

    Default Re: Rochester 2 bbl carb has no idle speed screw

    Idle mixture screws are just that mixture and NOT idle speed screws.

    If your idle speed screw is missing get one.

  4. #4
    Petty Officer 1st Class dr_bowtie's Avatar
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    Aug 2009
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    northern Indiana
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    281

    Default Re: Rochester 2 bbl carb has no idle speed screw

    which is it..? either you have one or you dont..?

    you stated in this threads as well as your other one the screw was too short...

    http://forums.iboats.com/showthread....=1#post2273667

    for the best/most help you really should keep this question to one thread you will not only confuse us but end up confusing yourlself...

    I posted thje manual with pics in one of your threads and you can clearly see the step-cam as well as the idle screw and so can you in the picture above...

    if the cam is on backwards remove it and flip it...if the screw is gone find another...match your carb to the picture matching the linkage and everything...

    noting it's exact position...yours should be the exact same...if the carb aint right do as another poster said and take it back...

    if the base gasket isnt on correctly it wont run right either...

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