I re-titled this thread because fuel enrichment seems to be more commonly used to refer to the choke on the Solex PAITA 34 carbs.

The valve rotates freely in the cover so it seems like installation options could be infinite. Fortunately, there is a slotted bolt with a stop lever that limits your options to basically 2. The common advice is that you can get these installed 180 degrees out which will cause all kinds of problems getting the car to run right. Seems like a lot of extra work to piece it together and then take it apart when you are trying to tune everything.

I will endeavor to understand its positioning prior to install. To that end, I traced an outline of the air passages on the cap on some wax paper and cut that out to lay over the respective portion on the carb body. This was easier than trying to visualize the passages when assembled. Then, based on the position of the slotted bolt and stop limits, I put the wax paper in its relative position based on the 3 choke positions:
Position 0, all the way in, normal running
Position 1, half way out, fast idle
Position 2, all the way out, full choke

See the pics below. First post are pics of the not yet dismantled carb (to keep for reference while rebuilding the other one) It's a bit hard to see but the position of the slotted bolt with the choke at position 0 is with the bolt roughly North/South. If you were to pull the choke to position 2, the bolt turns counterclockwise to face East/West, more or less. Right in between is position 1. Behind the linkage assembly is the stop limiter which rests on the two stops above and below the center bolt.

Attached Thumbnails

 

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Pic 1 would be choke position 0. Slotted bolt North/South-ish.
Pic 2 choke position 2.

Attached Thumbnails

   

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

A trace made by wax paper. The straight line on the paper is the relative position of the slotted bolt.

Pic 2 is choke position 0, pic 3 is choke halfway, pic 4 is all the way out.
Ink side of the wax paper has to face the carb body, keeping consistent with position of the valve cap.
Not the various options for lining up the connecting air passages. Doesn't seem to line up with anything very well. . .

Attached Thumbnails

       

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

This next set of pics represents the only other option for valve positioning based on the stops and slotted bolt. Same sequence with choke off, half, full.

Notice there seems to be a logic to the way the air passages line up. Choke 0 has no alignment of air passages, choke 2 has the most alignment.

Based on this, I think I'll choose this option for reassembly.

Attached Thumbnails

     

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Agree that the 2nd set of pics represents the correct way to orient the piece. Nice way to figure it out.

__________________
- Greg -
1973 220D, The Prodigal Benz
1974 240D