I know a little bit. You turn the adjustment screw in until the engine speed drops off, then back out ..... until WHEN?

Thanks.

I've used these in the past with some success:

http://www.webercarbsdirect.com/v/vspfiles/images/Weber%20Trouble%20Shooting%20Guide.pdf

http://www.carburetion.com/Weber/adjust.htm

Hope they help.

Thank you.

One says to back out until it starts running worse, then back in halfway between the two points. The other says to go back in to the fastest, smoothest idle.

Better yet, one has a photo that clearly shows the "vacuum advance port", which was a question I had in another thread.

I to am a Weber Conversion owner and must say after it was tuned in to the right spot I really like the carb. One thing I'd like to mention, try and get the engine up to normal operating temp before finalizing the adjustment. I also went back and tweaked the throttle screw so my idle was around 800 rpm.
My Opus ditributor is also a vacuum advance unit and requires the hose from the bottom of the carb ran to the distributor. Some say its not necessary but I have had nothing but good, smooth running with it hooked up.