Hi Knarf,
Are you sure you understand how the warm-up compensator works? From your post it seems you may not. Here's what should happen: As the warm-up compensator's valve is pushed more closed, either by the bimetallic spring being released when hot, or the adjustment spring by turning it in (clockwise), the closure causes MORE control pressure to be presented at the top of the control piston in the fuel distributor. This causes the piston to lower, leaning out the fuel mixture. NOTE that the pressure source is from an orifice within the fuel distributor to the control pressure line, and this pressure is only REDUCED by the warm-up compensator - the return line from the compensator goes to the fuel return line that returns fuel to the gas tank. The factory manual says the pressure is variable from 0.5 bar to 3.5 bar.

When the engine is cold, the bimetallic spring pushes against the warm-up compensator springs, lessening the pressure against the compensator's valve, allowing more fuel to bleed off to the return line, lowering the control pressure at the top of the control piston.

So, turning the adjustment in a few turns should have leaned out your mixture somewhat. I turned the adjustment on my 450SL's WUC in .050 to correct a too-rich mixture at idle. After "messing" with the WUC it is necessary to readjust the idle mixture using the 3mm allen wrench.

Regards,

__________________
Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C