Vacuum Break
- Place fast idle cam follower on highest step of fast idle cam. Using an outside vacuum source, apply enough vacuum to seat diaphragm. Push down on choke valve. Diaphragm plunger should be seated and bucking spring should be compressed (if equipped). See Fig 1.
- Measure clearance between lower edge of choke valve and inside air horn wall, using specified drill or pin gauge. On models equipped with delay feature, cover plug and purge bleed hole in vacuum break end cover with masking tape.
- On all models, to adjust, bend "U" shaped portion of vacuum diaphragm connector link. Remove masking tape. Check linkage for binding and freedom of movement.
Courtesy of GENERAL MOTORS CORP.