What is the lesser evil?

Discussion in 'The Venerable Q-Jet' started by Cutlass, Aug 25, 2020.

  1. Cutlass

    Cutlass Platinum Level Contributor

    What are your experiences / recommendations in regards to the idle vent valve:

    1. keep it functional, but have to crank like hell after the car was not used for a couple of days (fuel bowl empty)
    2. remove the idle vent valve lever (10), so that the valve is always closed, but risk issues with hot start
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I prefer the Q-jets with the vent in the air horn. That vent valve vents to the engine compartment if I am not mistaken. I'd rather have it vent into the air cleaner. I have a 7042240 72 Q-jet. I never have hot start problems, it fires right up. Gas will evaporate out of the bowl after 2 days. Even so, it doesn't take much cranking to fill the bowl, then a few pumps and it fires. I have the CV Products mechanical fuel pump. It has no vapor return.
    Cutlass likes this.
  3. shiftbyear

    shiftbyear Well-Known Member

    I believe is was discontinued for emissions reasons, so it must be good. Seriously, most HP factory Holley carbs also had the external vent valve. I always keep it functional on the rebuilds I do.
    Cutlass likes this.
  4. Cliff R

    Cliff R Well-Known Member

    That part is not needed and they disappeared in the early 1970's. There is PLENTY of venting area from the front vent and as mentioned and it contains the vapors inside the air cleaner assembly for the most part instead of venting them directly into the engine compartment.....
    Cutlass likes this.
  5. Cutlass

    Cutlass Platinum Level Contributor

    Thank you guys.
    2:1 for getting rid of it, so I will remove the lever, so that the valve stays shut.

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