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F-head running to rich.

Discussion in 'Early CJ5 and CJ6 Tech' started by Aaron, Dec 4, 2005.

  1. Dec 4, 2005
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
    Joined:
    Sep 20, 2002
    Messages:
    4,350
    Discolored?


    You did set the dwell.....right?
     
  2. Dec 4, 2005
    willysnut

    willysnut Banned

    Newnan, Ga.
    Joined:
    Oct 8, 2003
    Messages:
    654
    Slap in a new set of points/ condenser adjust and reply back, I had the same problem just after getting my jeep, would run when started but would stumble and run rough at idle, lots of black smoke, fouled plugs quickly(fuel). Did you have the key "on" while the jeep was not running? It sounds like you fried your points, it can happen very quickly if the point contacts are touching and 12v is running through them. :hurrican:
     
  3. Dec 4, 2005
    Aaron

    Aaron Got Primer?

    West...
    Joined:
    Aug 20, 2003
    Messages:
    57
    will do thanks for your help everyone.
     
  4. Dec 4, 2005
    Ducks-Bass-n-Jeeps

    Ducks-Bass-n-Jeeps A Parade of One

    Brentwood, Tennessee
    Joined:
    Aug 11, 2003
    Messages:
    120
  5. Dec 6, 2005
    willysnut

    willysnut Banned

    Newnan, Ga.
    Joined:
    Oct 8, 2003
    Messages:
    654
    Any help?
     
  6. Dec 6, 2005
    Aaron

    Aaron Got Primer?

    West...
    Joined:
    Aug 20, 2003
    Messages:
    57
    Alright just put in new points and condenser,adjusted them to specs and started it up.Ran much better but was still rough, so i guess that the valves are the cause of the problem and when i have more time they will be adjusted.
     
  7. Dec 8, 2005
    kamel

    kamel Senior Curmudgeon

    Erlanger, Kentucky
    Joined:
    Jun 10, 2003
    Messages:
    891
    If you are getting black smoke then the problem is fuel.

    If the problem is running rich then here is what I'd suggest.

    Rebuild the carb.

    Again?? Not again???

    Yes, again. Only this time use the kit from www.thecarburetorshop.com

    It'll cost you around 40 bucks but it is the right kit for your carb.

    Also, be sure to replace the float valve you have in the carb now with the valve you get in the kit.

    Do NOT mix and match parts between the kit you buy now and the kit you put in the first time.

    Re-adjust the float to JEEP specs in the kit you get from the carburetor shop. If they don't give you the specs, ask Jon at the carburetor shop what the correct level is for a Jeep application.

    You will need the carb number off of the webbing on the side of the carb in order to get the right kit.

    It'll be most likely 938SD, but could be some other number.

    You cannot mix and match parts between two different YF carbs. The parts will fit, but there are subtle differences between them and you will get lousy performance.

    It took me around a week or so to figure out a carb problem earlier this year on an F head. Turns out that the previous owner took all of the 'good' parts from several YF carbs (that were different models) and put them in one carb.

    I had to cull them all out - that isn't fun at all.

    kamel
     
  8. Dec 9, 2005
    rmtaunton

    rmtaunton New Member

    Atlanta, GA
    Joined:
    May 10, 2005
    Messages:
    23
    id start with the valves ,,i have a hour meeter on my 3b and right about 150 hours i re adjust them ,,,sometimes i dont think i need to ,,but after i do i always notice a huge improvement the f head valves do move out and sometimes it hard to notice since its so slow ,,i reccomend to everyone ,when ever they want to tinker on the f head ajust the valves I have small (about the 4" size )zipties that measure out perfect for gap on the pointy in , before the grove starts ,,it makes it real easy
     
  9. Dec 10, 2005
    Missouri 71

    Missouri 71 Member

    Imperial, MO
    Joined:
    Dec 10, 2005
    Messages:
    129
    You're having the exact problem my Carter YF is.
    Even after a thorough and meticulous rebuild.

    I tracked it down to excessive play in the throttle shaft causing a vacuum leak and an incurable bog.

    Give your throttle shaft a tug-back and forth, up and down.
    See if it's sloppy at all.
    Even a little slop is not right.
    If it's bad enough (like mine), you can do the shaft test while it's running and the idle speed will change.

    How to cure it?
    Tear down the carb. bore out the throttle shaft bores and have bushings installed.

    What am I doing to remedy it?
    I'm switching to a 2 bbl. progressive Holley (It's a dead ringer for a Weber 32/36) I've had laying around in my shop for a few years.
    It came from a 2.0 AMC 4 cyl. so it should be jetted well enough to start and see if it's going to work.

    Best of luck!
     
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