560sel flooding

I have a 1986 560sel v8 gas that runs fine until the engine warms up and gets shut off. Even if the car gets shut off for 1 minute after it's warmed up it starts to bog out and floods and is very hard to start. When it does start there is all kinds of black smoke coming out the tailpipe.

Is the fuel pump still running, when shut off? That might be a nice place to start. Also, one might find that their fuel pressure regulator is suspect, or that there is some kind of problem with your return line, leaving fuel at the injectors. That might be a nice place to start.
That is my first feeling , that your fuel system is either still running, or failing to return unnecessary fuel to the tank.