Carter - linkage adjustment

Discussion in 'The Mixing shop.' started by colonel, May 28, 2017.

  1. colonel

    colonel Speedjunky

    I have a 340 AT w/Carter 4bbl in LeSabre. Car starts, idles fine and drives ok upon slow acelleration, but stumbles if gas pedal is pressed down hard and doesn´t "fly" as a 260hp car should (even with roughly 4,000 lbs.)

    Checking on the carb I found the blade of the primaries not opening completely upon full throttle. However, the lever on the lower part of the carb moves until it hits a stop. Here´s a pic, notice the position of the blade:


    And the corresponding position of the lever:


    I then found out I can manually move the linkage/rod to the carb blade further into the fully open position. See the position of the blade:


    and the lever:


    Knowing, that adjustments can be done by bending the tangs and rods, it´s hard to belive that those metals parts have moved about half an inch over time all by themselves.

    Any ideas what might have caused the problem and how to cure?

    FWIW, this part got busted, too, but I doubt it has anything to do with it?

  2. 455monte

    455monte Well-Known Member

    Thats your choke blade.
    Its going to be partially closed until engine is warmed up. U should have a coil type choke on other sideof carb with a hot air line from the exhaust manifold. if working correctly blade should be verticle when engine is fully hot .
    If not then your killing gas milage and running rich and restricting airflow into engine.
    Don't bend any rods ot tangs! Not necessary
  3. flynbuick

    flynbuick Super Moderator Staff Member

    Once you repair the stumble, you will still have only about 150 HP to the rear wheels in a 4000 lb. car. The engine when new and was about 200 HP SAE Net, the standard used today. When it was rate 260 HP in 1967, the now obsolete SAE Gross standard was in effect. So your power to weight ratio is about 20 to 1.
    Last edited: May 28, 2017
  4. colonel

    colonel Speedjunky

    Thats what I found out when I went back to the car to work on it. I must have been still sleeping when I posted this morning. Thanks for clarifying
  5. colonel

    colonel Speedjunky

    You are right about net and SAE, of course. How do I get rid of the stumble, check and adjust timing?
  6. wkillgs

    wkillgs Gold Level Contributor

    The stumble could be caused by a faulty accelerator pump. Is it undrivable unless you very slowly ease onto the gas pedal, and it stumbles with any more?
    With the engine off, look into the carb and pull the throttle lever back, you should see a good stream of fuel coming from the squirters. If not, the accelerator pump system isn't working properly or your fuel bowl level is too low.

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