I know what the book says, but what does your C3 idle at when warm...

In Park/Netural?
In Gear at 0 MPH?

My answers right now are: 1300 and 600.
1300 seems high, but if I turn it any lower, my 600 becomes 400 and the car wants to stall when stopped in gear.

Also, am I right that there is only one idle adjustment screw?

|UPDATED|11/4/2003 7:28:37 AM|/UPDATED|

my 81 is at 900 park/nuetral, 6-700 in drive at 0 mph. the last time i took it to my mechanic for an engine problem he put it at about 13-1400 in park, and that really irritated me, because i would have to turn it off in drive, or else the engine would keep cranking with no spark wich sounds bad, but i don't know if it really is.
hope i helped

My 80 l-48 in neutral idols at just above 5 . In gear , right at 5 . My engine has mods in it though. What carb are you running ? Do you have an hei dist. ?

|UPDATED|11/4/2003 7:29:05 AM|/UPDATED|

I setup my idle at 1100 in neutral and it drops to 700 when in gear with my foot on the brake.

My 78 L-82 Idles at 1600 till it warms up and then comes down to 900 with the stock Q-jet, The only thing not original about my engine is true dual exhaust with no cats and no A.I.R. pump. These numbers by the way are exactly what my Haynes repair manual says they should be, as I've never seen an original chevy shop manual for the car I have to assume this is correct.

Mine cold idles at 1500, then kicks down to 900, then kicks down to 750 when fully warmed up.
Sarge

Adam, there is two idle adjustment screws but if you have AC on an 80ish year there is also a solenoid that kicks in to increase the idle setting when the AC is selected. Be sure to check the idle setting on this as well. One screw is for regular idle and one for the warm up fast idle.

You should be able to adjust your idle setting fairly accurate. I keep mine around 650-700 in gear with the brake on and no AC selected. If I start getting much below 600 I start getting a noticable increase in the lope of the engine and start having low vaccume. The AC setting I have it set around 700. In park it goes up a little bit but not that much. I can't give you the exact numbers now, my carb is out getting completely refurbished, should be back in next weekend. Anytime I had my idle set over 800-900 it would clunk when going into gear from park to neutral.

|UPDATED|11/15/2003 7:25:09 PM (AZT)|/UPDATED|

Don't forget the fast idle adjustment. It adjust the idle when it's cold and when you stomp the gas it comes off and then it's your idle.

You can leave your idle adjustment where it is. All you do is turn the fast idle adjustment down to what you want.

Adam, I got my carb back on. Like Gymbo said, there is a fast idle adjustment, it is located on the passenger side of the carb below the choke area (the screw head faces forward). Adjust when the engine is cold to 1200-1400 in neutral.