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Thread: Fast Idle Hanging Up

  1. #1

    Angry Fast Idle Hanging Up

    I've got two Holley's with electric chokes that are both doing the exact same thing on different vehicles. One is a brand new Street Avenger and the other is an older 4160. I even used to have an older 4150 that did the exact same thing. The fast idle will not kick down all the way after the engine is warm, it is hanging up on the last step of the arm. I can get it off high idle by pushing the arm down with my finger but as soon as I touch the throttle it hangs up again. I have a full 14V when the engine is running. The arm itself seems to swing freely. I've tried adjusting the fast idle screw out but that hasn't resolved it, it has only lowered the idle. I've tried searching but haven't found what I need. I've tried leaning out the choke but that doesn't help, I end up too lean and now that it's winter, it's almost undriveable.

    I'm not sure where to turn next, any & all suggestions are appreciated.

  2. #2


    I have the exact same problem with my Street Avenger 670. I have been searching all over and can't find a solution.

  3. #3


    Did you ever come up with a solution? Have the same problem with a 670 SA, and haven't been able to find anyone that knows what causes it.

  4. #4


    If you adjust the choke housing, choke blade, and linkage properly. Then it will have full travel.
    1. The choke spring only has so much travel. When cold to hot (heated by the 12 volts). If you try to exceed this limit. The choke will not fully release the "weighted speed step". The part you folks are saying that's "sticking".
    2. The choke blade should not be 100% closed when setting up the choke adjustment. You should have a small gap between the top of the choke blade and the airhorn. 1/16 to 1/8" works fine.
    Note: Some carburetors have a "suck valve" on the choke blade. It lets more air in, if the choke blade is closed too much. If the carburetor has one, use it as a tunning aid.
    In other words: If on a cold, choked engine. The valve is opening. Adjust the choke to have a larger gap between the top of the choke blade & air horn.
    3. The choke spring housing (behind the black cap) has a "controlled vacuum leak passage". This is used generally for two purposes.
    A. It lets in air to cool the 12 volt choke spring. It will burn up with out the air.
    B. Some springs are connected to a mini connecting rod & piston. The vacuum leak sucks the piston in, and helps open the spring. Without it, the choke blade could be held in the closed position by the velocity of the air rushing past it.
    Note: Make sure the piston moves freely, the passage way is clean from the outside of the choke housing to the base of the carburetor, and you have a gasket between the choke housing and the body of the carburetor.
    4. The rods are to be installed dry. Never use any type of lubrication, or grease on them.
    5. The three basic rods used on electric choke carburetors.
    A. From choke spring to lever on "thick" rod that goes across the top of the carburetor.
    General leave this one alone (don't bend it). If it's a used carburetor, it might have been bent, or replaced with the wrong one.
    Why would you adjust it? To get it to line up with the markings on the black plastic choke cap, and the marks on the aluminum choke housing. This sets up that piston I was talking about, to be in the "right" place.
    Note: You need to adjust the next two rods first. Before you can even think about adjusting this one!
    B. This rod goes from the choke blade to the middle of the thick rod that goes across the top of the carburetor.
    If it "feels" like the choke is not opening, or closing all the way from the "heated choke spring". This is the rod to bend.
    Note: The heated choke spring might need to be replaced if it's off a lot. You should not have to bend the spring that much. 1/16" or less is ok.
    C. The rod (on the throttle level side of the carburetor) that goes to the "weighted speed step" lever.
    This is easy to adjust: Unscrew the fast idle speed screw untill there is no way it could be touching any of the steps. Then open the choke all the way. The weighted lever should be at it's lowest position. Bend the rod a little to get it there.

    Why would you need to do these adjustments for a new carburetor you just removed from a box?
    Because it's the wrong carburetor for the application. The rods had the wrong bend in them.

    Tip: Never use an electric choke carburetor in a dusty/dirty environment, or on a "true" high performance engine. The controlled vacuum leak at the choke housing is not filtered air!

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