Center Carburetor Only

Press in on diaphragm plunger until it is seated, close choke valve as far as possible so that diaphragm connecting rod is at end of slot in choke shaft lever, measure choke valve opening by inserting gauge or drill rod of correct size (see table below) between upper edge of valve and air horn wall. If valve opening not correct, adjust by bending diaphragm connecting rod at the angle (see Fig 1).

Fig 1: VACUUM BREAK DIAPHRAGM ADJUSTMENT (2GV CARBURETORS)

Courtesy of GENERAL MOTORS COMPANY