1969 C10 Holley Carb help please

[Ben IV]

Originally Posted by csfdfirefighter

I checked the float level some time ago. I found these instructions for doing the pump lever but the instructions describe “First, make sure that the fast idle cam lever is disengaged so that the operating lever opens all the way.” I’m not familiar with what the fast idle lever is.

Any pictures I see of a similar carb on the internet shows another accelerator pump nozzle on the secondary side.



https://www.holley.com/blog/post/how...retor_stumble/
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Fast idle lever is part of the choke. Brings the idle up when the choke is closed.

Your carburetor is a 670 street avenger. Great carburetor I've had the same one on 2 different trucks. It is a vacuum secondary carb so only a discharge nozzle and accelerator pump on the primary side. The pictures you see with 2 are mechanical secondary carbs "double pumpers"

Holly has some great videos on tuning their carbs. You may be able to fix your hesitation by changing the pump cam. They sell an assortment and there is a chart showing which cams do what. I swapped the factory orange cam for a blue cam and it helped in my application. Your results may vary.