I'm sorry, but your parts changer mechanic doesn't have a clue. I have used that same Crane unit on several early V8 Mercedes cars and have never had an issue.

Those cars are NOT meant to run rich, he probably doesn't have a proper co meter to measure the co content. That is how the fuel mixture is set up on these cars. Obviously, the ignition system has to be sorted out first.

It sounds like this guy is a parts changer, not a technician.