At 04:51 PM 7/6/2012, neil n wrote:
>would allow the AFM to stay closed. e.g. that air bypassed this flap
>and that the mixture was controlled by adjustment of air only, via the
>CO screw. Not true it seems.

No, it's a trimmer.  See
https://picasaweb.google.com/dbeierl/VanagonWBXAFM?authuser=0&feat=directlink
for the rough area that the vane oscillates about during idle.  If
the lighting in the photo had been different you'd have seen the
additional wear spot on the carbon track.

On the air cooled engines the AFM also must be open for the fuel pump
to run; on the WBX they changed over to use the distributor pulse,
saving the expense of an extra switch and some wire.

Yours,
David