Accelerator Pump Diaphragm Assembly, Early Model Weber IDF

This Weber IDF accelerator pump diaphragm has a spring-loaded (not solid) center button. This "cushions" the diaphragm against being pushed too far. (Later IDF "XE" carburetors used an adjustable, sprung linkage to prevent over-travel.) Sold individually, one per carburetor.

Note: The sprung button in the center was originally metal but was later changed to plastic. Weber supplies the same part number with either a plastic or metal button at their discretion (sorry, no choice).