Weber 38

I installed a weber 38 on my 86 B2000. Problem I have is when I first start it, it wont idle right it keeps trying to die so I have to keep my foot on the gas. My question is I turned the fast idle 1.5 turns before I started my truck I turned the truck on and it could idle by itself, However once warm it would not hold the idle it would keep dying until I turned the screw back out 1.5 turns am I just turning too much or is there another issue here. I tuned the carb by ear when I installed it after it warmed up just like the instructions said. When the truck is warm it idles at 900 RPM fine with the screw turned out. I also tried playing with the idle screw but it would not keep running when warm unless I turned the fast idle screw back out.

too lean, or vacuum leak. I'd check for a vacuum leak. My truck had an infuriating vacuum leak till I fond it finally, it was the advance canister on the dizzy.

Found it!! PCV hose was severly cracked and broken. It runs great now! Thanks for the help russ!