Could this be Inj seals?
 

I have a 90 300 sel with 140,000 klm on it. It isn't driven a great deal but lately it starts up perfect when cold but if I shut it off and restart after 10 minutes it will sputter for a few seconds and I can smell fuel. After it clears up it is fine until the next time. I thought that maybe injector seals are letting fuel down on the cyl after shut down. What else could it be?

Sounds right to me, although I suppose it could also be a bad fuel pressure regulator allowing fuel to be pulled into the intake, creating a flooding condition.

I thought the injector seals just keep air out, the injectors themselves would be responsible for leaking the fuel, if that is what is happening..... The O-ring on the base of the fuel distro can also leak I am told, and cause the same flooding issue.