With the throttle in the curb idle position, the pump piston stroke adjustment (distance from the vacuum passage casting to the center of the hole in the pump operating rod) should be 27/32”.
NOTE: This test can be made on or off the vehicle.
The choke diaphragm adjustment controls fuel delivery while the engine is running. It positions the choke valve within the air horn by action of the linkage between the choke shaft and the diaphragm. Depress the diaphragm with a small drift.
Insert specified drill between choke valve and wall of air horn. Apply sufficient closing pressure on lever to which choke rod attaches, to provide a minimum choke valve opening, without distortion of diaphragm link. Note that the cylindrical stem of diaphragm extends as external spring is compressed. This spring must be fully compressed for proper measurement of vacuum kick adjustment.
An adjustment will be necessary if a slight drag is not obtained as drill is removed. Shorten or lengthen diaphragm link to obtain correct choke opening. Length changes should be made carefully by bending (opening or closing) the bend provided in diaphragm link.