Thanks for all your input. Jim (Fbody69) also offered some insight. I first will copy and print all your suggestions, then sit down in front of my carb and will try the easiest solutions first (I will send a prayer in case they will help...).

If it´s not the easy way, I´m afraid I then will have to drink some beers to have the nerve to go on any further...
I still didn´t understand all what I´ve been told but probably I will do after a few beers...

If you ever should hear about a drunken german Firebird driver who was fished out of the Isar (that´s a river crossing Munich) where he dropped in because he couldn´t stop his car anymore -- that´s me, after several tries and errors to fix my carb. Of course, everytime accompanied by some test driving...