If anyone has an extra Zenith dual carb linkage set up for sale please PM me with a price. Mine is completely missing.
There are at least 3 sets of the carbs on Ebay.
Maybe get in touch with one of the sellers, see if they can help.
Cheapest set of the carb there is $79. There is a Weber setup, new for $840.
It looks like one of the fuel lines into carb was disconnected when you looked initially. The metal isn't shiny so it appears it was like that for awhile.
Mercedes Late W111 220S 230s Zenith Dual 2 Carburetors Zenith 35 40 Inat T1 | eBay
Has a lot of really good plix in high res with decent light.
If fuel line was left open it could be dirty. Don't know these specific carbs but that inlet point on Rochester carbs of the era had a small metal fuel filter right there at carb inlet. (RED
It certainly looks like PO was working on a fuel/carb issue.
It also looks like he didn't finish, or it would be back together.
And if it sat in a dusty field for 3 years with fuel lines open....
When fuel is in carb and the float reaches top, the accelerator pump should work. It is a little triangular tab that turns upward while throttle opens. If there is fuel in bowl, opening throttle should cause a spray of fuel, even with engine off. Usually only get 1 or 2 of these without fuel pump running. But that would show when gas is available in carbs.
So you should be able to move throttle open and see gas spray and smell it. (Accelerator pump on front carb is BLUE
If carbs leak at all, they will need to be rebuilt for sure.
I see at least 2 vacumn lines not connected. The one on upper left in GREEN
is some sort of idle advance, likely for cold start or AC operation. In these pix, it is connected with a red line, might help to do the same, if nothing else it will stop one vac leak.
It really looks like someone was in middle of repair and walked away. You will need to find good images of where all of the lines went. Some vacumn lines are such that if they aren't connected or plugged, the car won't idle for sure.