Protective ball ???? Pictures ??

When I pulled the fuel dist on my 91 300SL ( M104 6 cyl ) the 3 ish screws near the top center of the dist were all that needed to be removed. There are some screws near the fuel injector tubes that lead to adjuster screws from what I recall so ne need to pul them.

Have a look at 190rev dot com , there has to be some info there.