Engine stalls on half throttle

Discussion in 'Ranchero Tech Help' started by FordR500GT, Aug 11, 2019.

  1. FordR500GT

    FordR500GT In Maximum Overdrive BRONZE MEMBER

    Chaparral, NM
    So, went on the maiden voyage in the 72 yesterday. All was good except it always seems to give me hell if I give it some throttle (about halfway). Timing is set at 8°, idle at 690 RPM. There is only slight hesitation on the throttle in park, but enough to kill the Engine in drive. No backfire or cough, just total loss of power. Engine dead no stumble. Idle mix is set about as good as I can get it. Seems to have gotten slightly worse from yesterday.
    Absolutely no issue on quarter throttle or WOT
    Rebuilt 2150 carb
    Last edited: Aug 12, 2019
  2. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Everett, WA
    Sounds like the accelerator pump runs out of go juice before you get halfway. Do this: start the engine, get it warm, then grab the pump lever and pull it toward the front of the engine. Hold it until you go to open the throttle, let go of the arm so that as you open it, the pump gives a bigger shot. Of course, do not hold your face over the carb. If it doesn't stumble at all or only slightly stumbles, the accelerator pump is not giving a full measure of gas as you open the throttle. So you can change the settings on the pump lever push rod (including changing the bends in the rod, to make it longer. I had to do that to Babe's new carb to get rid of the stumble on opening the throttle.
    FordR500GT likes this.

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