I have almost exactly the same problem with my just purchased 1981 380sl. Starts and runs acceptably from cold but starting it when the engine has been warmed up is a struggle. When warmed up the car will stall at lights unless I put it in neutral and rev it up to about 1200.

What is the OVP that was mentioned and is it hard to acquire one? Sorry, I'm quite inexperienced with cars, but eager to learn! I've taken a look through some of the other mentions in the forum for OVP but am no wiser yet.