Originally Posted by spectre6000
I'm not 100% sure on the function of this particular section of the linkage, but here's what I think is going on.
The linkage circled above is actuated by the vacuum pot.
That's called the choke breaker, and it is actuated by a vacuum diaphragm. There isn't really any emissions stuff on a '73 Land Cruiser carb.
When properly adjusted, the choke is fully closed by the linkage when it is operated by pulling the knob out all the way inside the cab. However, once the engine fires, there wouldn't be enough airflow to keep the engine running. The choke breaker vacuum diaphragm is connected directly to manifold vacuum below the throttle plates. As soon as the engine fires, manifold vacuum is applied to the vacuum diaphragm and it opens the choke plate just enough to allow enough air in to run the engine at the high idle setting (set by the high idle adjustment screw).