Firstfives.org

Assuming the timing is correct, what does the idle screw do ?

Throttle body, large brass. I know turning it out, anti-clockwise, allows more air, raises idle at normal operating temp. That also seems to invite a higher idle on start up, and the aux air valve to get involved in a game of rev drop, up and down with the idle switch.

Can the idle screw be turned out enough to effect throttle response ? Behaving as if starving for fuel, sucking air, accelerating ?

Back to my post that got ignored in a pile of acronyms: Idle switch, timing, trailer hitching, etc.

Thank you,

I kind of covered it in your other post, but I'll go into a little more detail.

Technically it allows air to bypass the throttle butterfly, which should be nominally closed to the point where if it was closed any more it would be binding. It allows a more reliable and repeatable idle. It does not affect response or mixture because it is bypassing metered air, that is air that has already gone by the air flow meter and is "counted" in how much air is flowing and consequently how much fuel is to be injected.