ORIGINAL: pierretopping
A is where the servo rod is attached to the link. The "hole" (sorry, don't know what its called) between B & C will not open like it should ?
Pierre
Another suggestions is to see if you can close the carburetor manually.
Disconnect the servo rod from the "hole" (or from the servo) and move the arm manually to see if it can close that way. This will let you know if the problem is in the carb or perhaps a linkage/binding issue.