OK. Got the car fully warmed up & very slowly turned the lamda screw in 1/2 turn at a time, every 3-5min or so. Same result every time. Brief journey to the 40% range, followed by a drop all the way down to 99% (.1v). I didn't dare go any farther after 5 full turns, lest the damn screw fall right out.

However, if I manually push the AF plate just a millimeter, the idle smooths right out & Duty Cycle shows around 45% & oscillating. Is it possible that something is wrong with the screw?

Or do I just need to adj the height of the AF Plate with the drift-pin on the top of the mixture unit?

I'm pretty surprised that moving the screw that far didn't get me anywhere...

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Currently:
1972 350SL Euro 4spd
1973 BMW R75/5
1981 BMW R80GS
1995 FZJ80 with OM606 Conversion In Progress