Wow ARCH, I think you may have just answered your own question!!Sorry, the mixture screw will affect the idle when setting the mixture, it just doesn't stop the problem no matter if it's lean or slightly rich. The idle speed screw is less than maxed out. If I set the idle speed up to 1500 it does not die but I can't stand that high of an idle. The crazy thing is that small adjustments of the idle speed screw have no effect on idle speed. The more I ponder the situation I am beginning to think something is wrong with the butterfly valves, possibly loose or binding on the spacer. I have had nothing but problems with this new Weber. First, the float valve was shot right out of the box and I had to replace it. The choke butterflies were sticking and would not close when cold and flooring the gas pedal. I found that if I loosened the butterfly screws a bit they worked fine. I may pull the carb tomorrow and inspect the primary butterfly for some malfunction.
This is my first experience with Weber and so far I am not a fan.
Just an FYI, I was a Volvo Master Tech for 30+ years so I am not a newbie. Thanks for the advice!
Meaning if you had that many problems out of the box with that weber I'd lean towards you have a defective carb.