What is the size of the Allen Wrench used to adjust the screw which is accessed through the hole in the Air Cleaner ? This is for CIS injection systems as in my 84 380SE.

I was having a starting problem where the morning start was great (because Cold Start Valve providing extra fuel). Thereafter, trying to start even after 5 hrs, it used to take 30 turns of the engine to start it. I noticed that the throttle plate was not lifting. I want to try to tweak the CO adjustment screw and see if that makes a difference. Is this the right approach ?


Thanks,

Amit