My '72 142E is acting up. When accelerating from an idle the car hesitates, the engine shakes, and finally it gets going. Possibly related is an inconsistent problem with starting the car. Sometimes I have to turn the engine over several times to get the car to start, all the while it blows out black smoke and smells like fuel. These problems have survived despite the fact that I have replaced the distributer, trigger points, cap, rotor, ignition points, and condenser. The ignition timing is set at 10 degrees advance. Does anyone out there know what is going on?