Frustrated with my 190E

I have a 1989 190E with a 2.6 engine, the car mixture has been on the rich side for a while, I know it because of the black smoke, now after a month of this the engine just quited, these is a description of the problems: the engine will start for a few seconds and then it will stall, if I press the gas pedal down the engine will stall anyway, if I keep on starting the engine it will not start anymore, after close inspection of the sparkplugs I found that they would be wet with gas, I have a good spark, I have checked all the ignition system and is ok, the fuel system is another story, there is a fuel or mixture regulator that is attached to the fuel distributor that is leaking gas thru a small vent hole? I adjusted and cleaned the plunger of the fuel distrubutor and I have to check fuel pressure. Any hints on my case?.....................