setting the idle speed?

[teggy87]

i cant figure out exactly how to do this, i know i can adjust my idle, and i can adjust my F/A mixture ratio, but is idle speed something totally differrent? im a little puzzled.

 

[66 Fastback]

Setting the idle and idle speed is essentially the same. The idle speed is adjusted with the screw that is a stop against which the lever on the throttle shaft rests against. Screwing it clockwise typically opens the throttle plates further and increases the engine rpm at idle.

Idle speed for an automatic transmission is set with the transmission in Drive and the parking brake on and preferably with someone in the car pressing on the brakes. So if the spec calls for the engine to have an idle speed of 600 rpm in Drive, when it is in park it might actually be running in the 800 - 900 rpm range.

A manual transmission equipped car just sets the idle speed with the car in neutral.
Doug

 

[Frankenstang]

and i can adjust my F/A mixture ratio, but is idle speed something totally differrent? im a little puzzled.

Just to add to the good info 66 Fastback gave you...yes, the idle speed is seperate from the idle mixture which is what I think you're referring to:

Idle mixture is adjusted by turning the idle mix screw. You can see the idle mixture screw (the one with a sping on the shaft) on this 1100 immediately to the right of the carb mounting bolt in the pic above, this controls the fuel mixture at idle.

Air/Fuel mixture ratio is fixed by the cfm of the carb and the size for main fuel jet installed. Rejetting the carb chages the A/F, so Idle speed, Idle mixture, and A/F are three seperate adjustments on any carb.