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Carb Confusion

Discussion in 'Flat Fender Tech' started by stang7222, Jun 30, 2020.

  1. Jun 30, 2020
    stang7222

    stang7222 New Member

    Long Beach...
    Joined:
    Jul 9, 2011
    Messages:
    27
    I've had my 51 3a for several years and the carb has been giving me fits on and off the entire time. Several rebuilds by 2 different guys that know what they're doing and I still have on again off again issues. I've decided its time to just buy a new carb. The problem is, what carb do I need?

    Its definitely an L-head. Don't know if it's original to this jeep. Right now it has a Carter YF but I don't know which YF specifically. All I can see on the webbing is "94"

    Do i get another YF? How do I know which one is the right one? Should I get a WO since that is likely the correct carb for this engine in the hopes that it'll bolt right on where someone else put this YF?

    Eta:
    block casting number: 641087
    Head casting number: 800376
     
    Last edited: Jun 30, 2020
  2. Jun 30, 2020
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    8,226
    Much info in the archives here, if you search.

    One overlooked factor with the YF is that it was used in many other non-jeep vehicles, but with some unique features for Jeep applications.

    The correct Jeep YF used a different float valve needle, and float valve, (The needle is spring-loaded, and the valve orifice is smaller, to prevent flooding in rough service.) The float height setting is also therefore different for Jeeps.

    Many generic 'over the counter' kits do not include those parts, nor do rebuilders always use the correct settings for Jeep even when they have the right parts.

    Also the YF is sensitive to fuel pump pressure, which ought to be about 2.5 or 3psi. Some people add an in-line regulator.
     
    Last edited: Jun 30, 2020
    scoutpilot likes this.
  3. Jun 30, 2020
    scoutpilot

    scoutpilot Member

    Asheboro, NC
    Joined:
    Jun 7, 2014
    Messages:
    320
    With a Flat Head L134 you can use either a WO (539, 596, 636, or 698) or a YS 637S.
     
    jeeper50 likes this.
  4. Jun 30, 2020
    stang7222

    stang7222 New Member

    Long Beach...
    Joined:
    Jul 9, 2011
    Messages:
    27
    Looks like I have an L head out of a dj3a...

    The studs that mount the carb to the intake are parallel to the firewall. Throttle linkage is on the rear of the carb and goes down to the side of the block.
     
    Last edited: Jun 30, 2020
  5. Jun 30, 2020
    IRQVET

    IRQVET Bubbaification Exorcist

    Tallahassee, FL.
    Joined:
    Feb 5, 2015
    Messages:
    680
    I got the Carter W/O repop from Joe's Motor Pool. Its not cheap, but it was plug n' play and works great . . . if you have something that needs to be rebuilt, my cousin swears by Scoutpilot. Again not cheap, but I'm told he does excellent work.
     
    jeeper50 likes this.
  6. Jul 1, 2020
    stang7222

    stang7222 New Member

    Long Beach...
    Joined:
    Jul 9, 2011
    Messages:
    27
    Wow!! All of the googlefu and patience i threw at this and I never came across Scoutpilot. What a wealth of knowledge! Thanks for the heads up. Looking more and more like a professional rebuild by an old jeep specialist is in my future.
     
    jeepstar likes this.
  7. Jul 1, 2020
    maurywhurt

    maurywhurt Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Western North...
    Joined:
    Dec 12, 2009
    Messages:
    724
    x2 on Scoutpilot....he rebuilt the carb on my GPW recently, and most definitely does excellent work!
     
    Last edited: Jul 1, 2020
  8. Jul 1, 2020
    Jeepinjase

    Jeepinjase New Member

    Gardnerville, NV
    Joined:
    Apr 8, 2020
    Messages:
    2
    Scoutpilot does excellent work!
     
  9. Jul 2, 2020
    jeeper50

    jeeper50 jeeps 'till I die

    Gawja
    Joined:
    Dec 20, 2007
    Messages:
    748
    As a Scoutpiiot customer his work is top notch. stands behind his work, sends video of your carb on his L head running.


    Great work! thanks scoutpilot!
     
  10. Jul 7, 2020
    Michael Wedin

    Michael Wedin Member

    Sweetwater, TX
    Joined:
    Mar 20, 2020
    Messages:
    59
    He did a great job on my YF, started right up after the engine rebuild! Even rebuilt my mechanical fuel pump. He has a web site (oldjeepcarbs.com) with lots of info . Videos it running on his jeep after every rebuild. Has several you tube videos on carb adjustments .
     
  11. Jul 7, 2020
    stang7222

    stang7222 New Member

    Long Beach...
    Joined:
    Jul 9, 2011
    Messages:
    27
    Pulling the carb tomorrow and going to send it to Scoutpilot this week. Thanks everyone for the info.
     
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