Choke PullOff Linkage
Choke Disconnects Secondaries
PullOff Linkage Spring
Fast Idle Cam
CHOKE CONTROL LEVER ADJUSTMENT (OFF VEHICLE)
- NOTE: If choke lever adjustment is changed, vacuum kick, fast idle cam position and choke unloader adjustments must also be reset
- Place carburetor on flat surface, flush against bottom of flange and extending out under choke control lever
- Push on choke lever (with throttle partly open) to close choke
- Measure distance from top of rod hole in control lever to flat surface
- Measurement should be 3 3/8"
- If not, adjust by bending link connecting the two choke shafts
CHOKE DIAPHRAGM CONNECTOR ROD ADJUSTMENT (1978)
- NOTE: If choke diaphragm connector rod adjustment is changed, vacuum kick adjustment must also be reset
- Ensure diaphragm is mounted securely to carburetor
- Use outside vacuum source to apply 15" Hg (or more) to choke diaphragm. Diaphragm stem should pull IN until fully seated
- Apply light opening (downward) pressure on secondary air valve
- Measure clearance between air valve and its stop
- Clearance should be .040"
- If adjustment is needed, bend connector rod at curved section until gap is correct
CHOKE VACUUM KICK ADJUSTMENT
- Remove air cleaner
- Open throttle manually
- Close choke and release throttle. This will trap fast idle cam at closed choke position
- Connect outside vacuum source to carburetor choke diaphragm. Apply at least 15" Hg of vacuum to diaphragm
- Press against choke lever hard enough to move vacuum kit adjusting tang against its stop. DO NOT distort linkage
- NOTE: A relatively weak torsion spring within the lever system can be deflected easily
- NOTE: Vacuum kit adjusting tang must be against its stop for accurate measuring
- Insert paper size gauge between bottom of choke valve and air horn wall at throttle lever side
- CAUTION: Do not change position of choke valve with gauge while measuring clearance
- If adjustment is needed, insert screwdriver in slot on tang and twist
- NOTE: Do not adjust diaphragm rod
- Check choke valve and linkage for free movement between open and adjusted positions
- Remove outside vacuum source and replace original vacuum hose to diaphragm nipple
FAST IDLE CAM POSITION ADJUSTMENT
- NOTE: If fast idle cam position adjustment is changed, choke unloader and secondary throttle lockout adjustments must also be reset
- Place fast idle speed screw on second highest step of fast idle cam against shoulder of high step
- Apply light pressure on fast idle control lever ot move choke valve towards closed position
- Insert correct gauge (.100") between bottom of choke valve and air horn wall at throttle lever side
- NOTE: Use care not to change choke position during measurement
- If adjustment is needed, bend fast idle connector rod at curved angle until correct gap is obtained
CHOKE UNLOADER ADJUSTMENT (WIDE OPEN KICK)
- Hole throttle valves in wide open (WOT) position
- Apply light finger pressure against fast idle control lever to move choke valve toward closed position
- Insert correct size gauge (.310") between bottom of choke valve and air horn wall at throttle lever side
- NOTE: Use care not to change choke valve position while measuring
- If adjustment is needed, bend tang on fast idle lever until correct gap is obtained
Choke Disconnects Secondaries
The secondary throttle valves are mechanically linked to the primaries and begin to open at 70 mph prox. During the choking phase, a pickup lever disengages to keep the secondary throttle valves from opening. When the choke opens and the fast idle linkage moves to off position, the pickup lever drops into position where it engages the secondary throttle linkage to open the throttle valves.
