The second butterfly in the pierburg is only opened under load through engine vacuum so it won't open when engine is off (or even with the engine idling or being revved). Choke looks like its set correctly with 3mm gap. Mine does the same when the engine is off.
Its a PITA when it goes wrong. Atleast its not the later model with all the electric gubbins too. Fast idle valve on mine is playing up at mo. Tries to idle at 900 revs cold which it doesn't like.
I did the throttle thing and my butterfly hardly moves ,just to check it will back off all the way there is a lever near the carbe body you can move and it should open fully [can post picture]...