Re: Holley Won’t Idle Down
NEVER hold the secs open if the carb is not a "4 corner idle model". The idle screw is to keep the secs throttle plates from binding in their bores, NOT to compensate for idle issues.
The ONLY time the secs are used to set idle is if the carb is a dedicated 4 corner idle design, most are not. The correct way to set regular secs is to back the plate positioning screw out a bit, so the secondary plates can totally close in their bores, then, set the screw to open the plates 1/4 of a turn, NO MORE. All this is made to do os keep the secs plates from binding in their bores at idle.
Also, using the secs to idle the engine on a 4 corner idle carb is tricky, the secs operate a bit differently, the engine would have to have a very long late intake valve closing time, very radical, to actually need secs idle help, so, most 4 corner carbs that aren't applied correctly, do not need the secs to be open to get a good idle, doing so can mess the whole thing up. Close the secs, set them like the regular carb, and try that.
One thing I do when I do with a Holley is to set the primary idle transfer slots to .020 open, with the idle screw, then, run a scribe across the front UPPER edge of the plates in their bores. This line is where the plates need to be for correct idle transfer slot positioning, and, you can see the lines and plate positions from the top of the carb down the bores, not having to pull the carb off the manifold to see the slots.