Recently after cleaning the throttle body on my '91 N/A the idle climbed and stayed solid at about 2500rpm. I adjusted is back down using the bypass air screw found on top of the plenum right near the TB itself.

Well now it is hard to start in the morning and sometimes when it starts it run very rough, uses way more gas and smell rich when idling.

Does anybody know the base setting for this screw? ( like: gently bottom then back out 2 turns, etc)

 

You probably have a new air leak. That screw will trim the only about 800rpm. You may have been adjusting it before the thermo-wax released the fast idle?

 

No, the engine was definitely warm. It's interesting that you say it only adjusts by about 800rpm though, 'cause it still idles at about 1500rpm these days!

What I would like to do is set the bypass screw back to normal and find another way to drop the idle down to the proper setting.

I'm sure that all I accomplished was to richen the mixture to a point were it dropped a bit, and in the process killed the power and gas milage too!