This is the bolt that holds the Accelerator Pump Jet (Part No. 1586-81, sold separately) in place in the Weber 32/36 DGV carburetor. It looks like a plugged banjo bolt, but it houses a one-way check valve for the accelerator pump circuit. If the valve sticks closed, the accelerator pump circuit will be clogged. If it sticks open, raw fuel may be pulled into the carb throat under vacuum, causing a difficult-to-diagnose rich running condition.
Fits Weber 32/36 DGV (including 5A)/DGAV/DGEV and 38 DGAS/DGES carburetors. Does not fit DFAV/DFEV or DGAF/DGEF.