[frydz1985]

So...

Can anyone explain what "fast idle" is?

More specifically, how can it be measured and what is its purpose/effect?

I have a holley street avenger 570, and the literature says that the "fast idle speed" is factory set to 1500-1600 rpm. That is really high for my idle, but maybe I'm not following what it truly means.

I currently have the actual idle set to around 850rpm when in neutral... so I'm not sure when the "fast idle" comes into play.

Thanks for any info.

-Frank

[Jmark]

Fast idle is use when the choke is partially closed and pulls up on a cam on the pass side of the carb to bump up the idle speed when cold. Once the choke warms up, the spring inside unwinds and drops the "fast idle cam" back down and you resume using the base idle screw.