Stuck idle mixture screws

Engine, Transmission & Driveline

  1. jct

    jct Senior Member

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    Trying to adjust my idle mixture screws and they are stuck as ever can be

    BBD-4423(ish)

    The lead plugs have been removed, not by me
     
  2. Joseph James

    Joseph James Senior Member

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    My understanding is those are factory set and not supposed to be changed. That's according to one of the service videos on YouTube with the little Tech guy.
     
  3. jct

    jct Senior Member

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    I saw those too...
     
  4. david hill

    david hill Well-Known Member FCBO Gold Member

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    Send me a pic of both left and right sides of the crab, I think I have a way to remove them.
     
  5. jct

    jct Senior Member

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    That's going to have to wait till i get my car back from the body shop; when ever i get my car back D-:
     
  6. david hill

    david hill Well-Known Member FCBO Gold Member

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    That's cool, PM me when your ready.
     
  7. rkrochen

    rkrochen Well-Known Member

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    Some of the manufacturers came up with this idea due to all the pollution controls and stated that these should not be adjusted. Problem was they ran like crap as they were set too lean. Depending on which carb and manufacturer some were simply covered by lead plugs whereas others utilized a stopper tab, I am not aware of both on any one carb. If it is utilizing the stopper tab you need to remove the stopper then they will turn. Back in the day we did this all the time when I worked at the dealerships. Need to see pics to know what method was used.
     
    • Thanks! Thanks! x 1
  8. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    The adjusting screws that were placed behind the lead plugs were never supposed to see the light of day again so they were often not anodized or otherwise protected from corrosion. This resulted in the screw seizing tight to the throttle plate. If they are not too bad, you can try soaking the base plate in some diesel to try and lubricate the screw threads to free them up. A lot of the time, the screws are going to twist off and you will probably need to find a junk carb and raid it for the base plate.

    Dave
     
  9. jct

    jct Senior Member

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    The base was from a used ebay carb used it for parts. Due to the the carb i had, had some bent shafts either in the base or the choke horn i kind have forgotten