V 2500 P/U 4WD V8-350 5.7L (1987)
Fig. 8 Idle mixture screw base adjustment. 1983-84 E4ME carburetors less letter stamping
MIXTURE ADJUSTMENT A
1.
Install gauging tool J-33815-2 or equivalent in ``D'' shaped hole on throttle side of air horn, Fig. 7, with end of tool positioned above open cavity
next to idle air bleed valve.
2.
Hold gauge down lightly to bottom MC solenoid plunger, then adjust idle air bleed valve so tool will pivot over and just contact top of valve.
Remove gauging tool.
3.
Start engine and run until it reaches normal operating temperature and dwell reading begins to fluctuate.
4.
Place automatic transmission in Drive (manual transmission in Neutral) and adjust idle air bleed valve to obtain a fluctuating dwell reading
between 25° and 35° (as close to 30° as possible), at specified curb idle speed. Bleed valve is very sensitive to adjustment. Adjust valve in small
increments, allowing time between adjustments for engine to stabilize.
5.
If unable to adjust dwell reading to specifications, or if reading does not fluctuate, remove plugs covering idle mixture screws as outlined under
``Concealment Plug Removal'' in the appropriate carburetor section.
6.
Turn each mixture screw in (clockwise) until lightly seated, then back screws out specified number of turns, Fig. 8.
7.
Reinstall carburetor using a new gasket, with air cleaner removed, and vacuum hoses disconnected and plugged as outlined on underhood vehicle
emissions label.
8.
Repeat steps 3 and 4. If unable to obtain specified dwell reading, proceed as follows:
a. If reading is below 25°, turn mixture screws counterclockwise 1 turn, then repeat steps 3 and 4.
b. If reading is above 35°, turn mixture screws clockwise 1 turn, then repeat steps 3 and 4.
