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I'm not a mechanic, so bear with me. I just had my Holley 650 double pumper professionally rebuilt, and then dyno tuned for A/F and timing. When the car is sufficiently warm, my idle speed creeps up a couple hundred RPM and idles too high. At this warm state, if I turn the idle speed screw to the right, the idle speed increases, but to the left of the original point, there is no effect. I can't get it to idle lower at this adjustment. I don't want to mess with the A/F ratio or timing. Why does it creep up on me? Where else can I check?

Thanks,
Troy
 

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You are right, do not mess with A/F or timing. Check to make sure the choke is not engaged. I bet it's sitting on the choke fast idle cam.
Dave
 

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Discussion Starter #3
It does have manual choke, and I though of that. I do have a little "binding" type feel when I push the choke all the way in, but when I check it under the hood, I can't force it open any further manually. I'll check with somebody who knows better how to adjust the manual choke....
 

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If you can back off the idle screw all the way without any effect, then you are going to have to remove the carb & back off the adjustment screw for the secondary throttle plates a bit.

It is normal for your car to idle higher after it's warm. The normal idle speed should only be arrived at after the car in warmed up.

Z. Ray
 

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go back to the shop that did the work and they can fix it with no problem i bet but if you start adjusting and then go back they may just tell you good luck.
 

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This is classic vacuum leak symptom. Try spraying carb cleaner around the base of the carb and around the intake while the car is running. If there is a leak, it will suck in the cleaner and the rpm will jump momentarily to let you know you found your leak. If you have power brakes, check all the connections for it as well.
 
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