Excellent link, Duke. That adjustment would need to be made
after the one I described. That one affects the mechanical operation of the fuel injection that's varying the
upper chamber fuel distributor pressure. That adjustment is really only an idle adjustment. It does change the duty cycle, but only at idle. MB calls it the CO at idle adjustment. That's why the steel ball over the screw, to keep you & me out of it.
good idle quality generally means a slightly higher CO at idle. Big deal.
The part that the duty signal goes to is the EHA. The adjustment I described changes the
lower chamber pressure in the fuel distributor. This is kind of an "over the whole range" adjustment. It seems to have the most effect on idle & just off idle operation. I'll bet there's an interaction between the two adjustments that the old-timers knew about, but never got written down. Ever get the feeling you're re-inventing the wheel? Or maybe just re-discovering it?
Mike, I just re-checked. It is a 2mm hex drive. It's the only adjustment on the EHA itself. FWIW, it's the second smallest of a Bondhus balldriver set. Smallest in my set is 1.5 mm.
BTW, it worked wonderfully. 90% improvement. Maybe another 45 degree turn this afternoon to make it 100%.