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Thread: Double pumper rebuild. Ran great, now fire, secondary squirting.

  1. #1

    Default Double pumper rebuild. Ran great, now fire, secondary squirting.

    Hi, I have a Pontiac 428 with Holley double pumper 700 cfm I think, on a '65 LeMans/GTO clone. I rebuilt the carb this summer, ran perfect. As it got colder, to put the car away for winter, I started it again. The carb backfired & fired twice at the carb. No air cleaner on at that point. I noticed that when not running, the secondary is squirting when I move the throttle. Is this normal? I thought only when the power valve opens or something, maybe I'm wrong. It is colder now than summer, maybe it doesn't like colder weather or a maladjusted choke? I think I have the mixture leaned in a bit, and I hear that may be bad. I'm just wondering if I blew out a power valve or something. I just winged the timing, but it ran perfect & responsive (in the driveway) over the summer. I could turn the key with no gas and have it start & idle, now I'm afraid as it catches on fire. Thanks for any suggestions.

  2. #2


    Sounds like no fuel in the primaries. Tap the fuel bowl with a wrench to unstuck the needle. Then adjust both needles. A "double pumper". Is what its name implies. Two "pumps". So when you floor it. The 1st pump squirts fuel to the primaries, then the 2nd pump squirts fuel to the secondaries.

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