This lever rides on a bushing on the primary throttle shaft of Weber DGV-series carbs. When the primary throttle opens most of the way, this lever begins to open the secondary throttle. The Secondary Return Spring pulls it back to the closed position when the primary throttle closes.
If you keep breaking secondary return springs, take a close look at the area on this lever where the spring hooks on. After a while, the spring can wear a groove in the loose lever. This groove can put a bending strain on the spring, causing the hook to break off after just a few throttle actuations. A new lever with a smooth hook area can help.
Fits Weber 32/36 DGV (including 5A), DGAV, and DGEV. Does not fit DFV series or DGAS. Sold individually, one required per carb.