S10/T10 Blazer 4WD L4-119 1.9L VIN A 2-BBL (1983)
Air/Fuel Mixture: Adjustments
Federal
IDLE MIXTURE ADJUSTMENT
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Set parking brake and block drive wheels.
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Place transmission in neutral.
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Remove carburetor assembly.
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Remove idle mixture screw plug using a screw driver inserted into the slit on carburetor lower flange.
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Reinstall carburetor assembly.
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Make idle speed and mixture adjustment with the following conditions:
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Engine at normal operating temperature.
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Choke open.
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A/C off.
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Vacuum lines for distributor, idle compensator and EGR valve disconnected and plugged.
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Idle compensator hose closed by bending hose.
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Turn the idle mixture adjust screw all the way in and back out 1 1/2 turns.
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Adjust throttle adjust screw to 850 rpm (M/T) or 950 rpm (A/T).
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Adjust settion of idle mixture adjust screw to achieve the maximum speed.
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Reset throttle adjust screw to above rpm.
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Turn idle mixture adjust screw clockwise (lean) until engine speed is down to 800 rpm (M/T) or 900 rpm (A/T).
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If A/C is installed:
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Turn A/C on "Max COLD" and set blower to high.
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Open the throttle to approximately 1/3 and allow the throttle to close. This allows the speed up solenoid to reach full travel.
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Adjust the speed up controller adjusting screw to set idle at 900 rpm.