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YF Carb woes

Discussion in 'Early CJ5 and CJ6 Tech' started by Olejeeps, Jan 5, 2005.

  1. Jan 5, 2005
    Olejeeps

    Olejeeps Dis Member

    Lincolnton, NC
    Joined:
    Oct 21, 2004
    Messages:
    18
    Hello all!
    Looking for some suggestions on YF carb woes!

    O-Hauled my YF (on a F134) and after much adjusting and jet and metering rod swapping, I have it now down to a High RPM, part to full throttle sputtering with black smoke. Performance is good in the bottom, even under full load (2nd gear, slight hill, full throttle from a near stop, no stumble at all!).

    Does this sound like maybe the fuel pump is overrunning the needle and seat at the higher engine speeds?

    Other ideas?

    Thanks for any help on this!
    Scott
     
    Olejeeps, Jan 5, 2005
    #1
  2. Jan 5, 2005
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    12,378
    Based on your description I'm leaning more towards ignition being the culprit.
     
    Glenn, Jan 5, 2005
    #2
  3. Jan 5, 2005
    Olejeeps

    Olejeeps Dis Member

    Lincolnton, NC
    Joined:
    Oct 21, 2004
    Messages:
    18
    Hmmmmm...
    Didnt consider that yet. Everything there is new, coil, cap, rotor, wires, plugs, points, condenser. May have to look at the distributor itself. Or maybe losing coil saturation? Charging system seems to be working okay. Battery is staying charged enough for repeated starting while Im messin!
    Am I missing anything on the ignition side here?
     
    Olejeeps, Jan 5, 2005
    #3
  4. Jan 7, 2005
    67cj5

    67cj5 Member

    Oregon
    Joined:
    Oct 15, 2004
    Messages:
    347
    I cant think of anything that would cause black smoke from ignition,but it never hurts to check your timing for the sputter ,but it is probally related to the smoke problem. Black smoke is an indication of too much fuel, or not enough air.Have you tuned the carb with a vacuum gauge? Also a good tool for timing
     
    67cj5, Jan 7, 2005
    #4
  5. Jan 7, 2005
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    12,378
    Performance is good in the bottom, even under full load (2nd gear, slight hill, full throttle from a near stop, no stumble at all!) My experience with the YF has been low speed stumble, and the metering rod adjustment is usually the culprit. It definitely could be dumping too much fuel via the float adjustment or maybe the needle's not seating good? The stock fuel pump shouldn't overcome the needle valve, but that's only a shouldn't. The higher rpm problem makes me wonder about the distributor though, worn maybe changing point gap at higher rpms?
     
    Glenn, Jan 7, 2005
    #5
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