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jetting a one barrel

Discussion in 'Intermediate CJ-5/6/7/8' started by sterlclan, Jul 4, 2010.

  1. Jul 4, 2010
    sterlclan

    sterlclan Member Sponsor

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    any source for smaller main jets? my wife has been getting a slight headache after jeepin never got em before the cam wondering if a smaller main jet would help with the gases that "may" be giving them to her....the plugs show a little rich and the pipe is black inside....carter yf one barrel
     
  2. Jul 4, 2010
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    The YF is a metering rod carburetor, and I expect you change the rod rather than the main jet.

    The metering rod provides "power enrichment" at low vacuum, analogous to the function of a power valve in a Holley or Motorcraft carburetor. I suspect the metering rod may be out of adjustment so that you have some enrichment at high vacuum. If anything, a factory tuned carburetor would tend toward the lean side, so it seems unlikely that the jet is oversized.

    I suggest that you read the few pages in the '74 or '76 manual here www.oljeep.com about the YF. This will provide an overview about the cicuits present and what you can adjust.

    hth! :flag:
     
  3. Jul 4, 2010
    Brian P

    Brian P Member

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    :iagree:
     
  4. Jul 5, 2010
    sterlclan

    sterlclan Member Sponsor

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    ok then where do i buy a new or smaller rod or jet?
     
  5. Jul 5, 2010
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    I expect you do not need a smaller needle - instead you need to adjust the position of the needle in the jet.

    http://oljeep.com/gw/76_tsm/Section4.pdf Fig 4-28

    The factory needle should be fine. There is no aftermarket source for needles that I know of. The F134 guys may know of a source, since this carb was used on 134s for many years.
     
  6. Jul 8, 2010
    sterlclan

    sterlclan Member Sponsor

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    got the book would i tighten or loosen the screw? I would assume tighter would lean the mix but stranger things have happened...
     
  7. Jul 9, 2010
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    If memory serves, the YF main jet is the same as a Carter AFB/Edelbrock 4bbl.
     
  8. Jul 9, 2010
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    Well, the '77 TSM I looked at gives you a procedure for adjusting the needle. I would follow the procedure. Once you've bottomed the needle, they tell you which way to turn the adjustment screw and how much.

    I don't have one of these carbs - only the book - and the book is not in front of me now. All I could do is repeat the TSM instructions, if I had them in front of me.
     
  9. Jul 11, 2010
    sterlclan

    sterlclan Member Sponsor

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    thanks I adjusted the idle mix and reset the screw and still seems a little rich runs mint though the wife outta get a gas mask.....
     

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