hey man ,, allso check your spark plugs , I had a similar issue and I though it was the carb but when my mechanic arrived we pulled out the spark plugs and it was completely blocked with engine oil ,, which means I need an overhaul , so I turned out to be cyl. 3 and 4 were not firing at all ,, honestly that was a suprise for me , for now its tuning good , but soon it will tease me again and ill be sure its not the carb .
and allso check this out ,, I looked for it for 3 months and I miss spelled something on google and it popped up : http://w123club.nl/images/fbfiles/W123/images/mercedes_carbs.pdf