W111 Zenith Carburetor Adjustment Help | Mercedes-Benz …
You can adjust the air volume via the idle control screw on each carburetor. Make sure to disconnect the linkage between the two when doing this. If the carbs are drawing air equally, but idle is unstable, there's likely an air leak somewhere, which is compromising the air/fuel mixture. This can have several causes, but a carb rebuild could be ...