Holley 4150 way to high idle.

Fuel and Air Systems

  1. Cope

    Cope Fusing with fire

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    Hi folks i need some help with my carb.

    Car is a 1971 dart 318.
    I just removed the dizzy to fab new kickdown linkage (not hooked up) and now I have an insane high idle, like 2,000 Rpm high (no tach).

    Curb idle screw is not even touching the cam.
    no matter how much timing I pull out I cant get a good idle?

    Timing is around 8 BDTC but to even get where it dosnet sound like my engine is gonna blow Im at @ 10ADTC.

    I have sprayed the carb with eletric parts cleaner and found no air leaks.

    Both main and secondary butterflys are closed. I cant understand how with all the blades FULLY closed it can even pull that much air?

    I just rebuilt the carb and it was working fine before I pulled the kickdown linkage and Dizzy.

    It dose look like a lot of fuel is dumping out of the primary discarge nozzles but I never looked before so I dont have a base line to truly judge off.

    Thanks for any and all ideas.
     
  2. AJ/FormS

    AJ/FormS The end is near FABO Gold Member

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    -Assuming you are correct when you say all butterflys are closed: Did the pcv line or brake booster line get accidentlly dislocated or cracked?
    -Its also possible that the PV is ruptured.
    -Curb idle screw and cam dont belong in the same sentence for 4150s
    - with closed blades the nozzles should absolutly NOT be flowing
     
  3. rmchrgr

    rmchrgr Skate And Destroy

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    I would look there. Clearly something was disturbed or not put together correctly. Re-trace your steps, it's probably something simple. Maybe you reversed a gasket uncovering a hole inside the carb or something.

    Kind of sounds like a vacuum leak. Cover the carb while its running, see what happens.
     
  4. TrailBeast

    TrailBeast Slightly Twisted Member

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    I'd bet on this.
    Totally sounds like a vacuum leak.
     
  5. Cope

    Cope Fusing with fire

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    Dam I feal stoupid..

    main butterflies were not fully closed....

    My new throttle linkage was holding them open almost a 1/4 inch...

    Gonna reset and see what happens...

    Face palm..
     
  6. BIG-B-Barracuda

    BIG-B-Barracuda Well-Known Member

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    I had the same issue, because I had replaced the base and gaskets of the carburetor/intake with thicker versions so because it was taller the throttle cable was throwing the idle off. Stupid mistake that I overlooked. Thank guys for the clear insight always turns out to be some thing small and simple.
     
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