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Thread: Need Help with Running Rich

  1. #1
    Psychopete Guest

    Default Need Help with Running Rich

    Hello, I have recent freshened up my Holley 4160 600cfm carb. It's on top of a 5.0L with a Ford B303 cam, GT40 heads w/ 1.6:1 roller rockers. Worked when it was on the truck, but wouldn't die when the passenger idle screw was turned all the way in, so I thought the metering block was plugged. It's a vacuum secondary with only the metering block in the front. It had been running slightly rich.

    So, I bought a Holley kit and cleaned the carb out real good with carb cleaner. Now it is running pig rich. Seriously "raining" fuel from the two front venturis. I have tried different power valves and smaller jets. It wasn't as bad with 61 jets and the original power valve, but still would run pig rich even with the idle adjustment screws turned in. I think it might be leaking internally?

    Floats are currently too low, no gas coming out of the sights, so that's not it, I can't even get this thing to idle. Seriously bellowing black smoke. Checked pressure since I am running a electric pump w/ a regulator and it was around 7.5PSI. Not sure where to go from here, any ideas what might be wrong?


  2. #2
    Join Date
    Nov 2009


    Seriously "raining" fuel from the two front venturis
    If you can actually see fuel coming from the boosters, then there are a few things for you to check. First, recheck your float level. This is the top cause of this problem. Next, check to make sure the primary throttle plates are not opened to much. If they are, you will be pulling a signal from the primary boosters, which in-turn, will pull fuel from them. Another common cause can be if the primary high speed air bleeds or the vent tube is clogged. You may also check to make sure the correct metering block gasket was used in the rebuild.

    Hope some of this helps.

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