Air/Fuel Mixture on 81 380SL

Upon starting my mercedes, a small amount of black soot comes from exhaust and stains the garage floor. It didn't do this before taking it to a mechanic for a fuel pump replacement. At that time he informed me that I needed a fuel dist. The car now also hesitates and has poor acceleration from a stoplight (with gas pedal fully depressed)until it reaches about 30 mph. At that mph is when it springs to life and accelerates like crazy. Here's my question: Being that it's running a little rich(soot), would it harm anything or make it accelerate any better from a stop if I were to turn the air/fuel mixture screw on the fuel dist. approximately one half turn to lean it out some?

[stevebfl]

Proper set-up requires centering the feedback control system: lambda. Check the DIY article on evaluating engine controls. Its pretty easy stuff with a couple common tools.