Weber Carburetor: Can we repair a Carb with a broken mixture screw?  

Roberto, it is always a pleasure to watch your videos. Yes, and always impressed.

18:13 as you are unscrewing, the broken tip falls through the fuel feed tube, into the float bowl, and bounces out onto the bench. Fortunately, it didn't lodge in a gallery. Next time: don't have the adjusting screw in, rotate the assembly 90 degrees so that the tip falls out of the adjusting screw hole, and position your counter-snipers on the roof.