Mercedes: v230 poor starting when hot, massive air, open throttle

Question
hello, i have just bought a 1997 v230 which starts fine with no throttle when cold but takes a very long time and needs throttle held down when hot or after being left for a short while.( it will start fine if it is restarted straight after being switched off)if it does start without throttle when warm it will run very rough until you rev the engine and then it will pick up. i have checked plugs and they are sooty. any ideas? many thanks. phil

Answer
I have no service data on this vehicle.
Best guess:
The issue sounds like a leaking cold start valve, flooding after warm shutdown.

This would explain the spark plug soot and need for wide open throttle = massive air intake to give relief of flooding condition.