Idle Speed & Mixture

NOTE: Mixture adjustment is NOT a part of normal tune-up procedure and should not be performed unless carburetor is disassembled or vehicle fails emission testing.

If mixture needs adjustment, remove carburetor from engine and place in holder. Drill out concealment plug. See Fig 1 . Drive out roll pin. With plug and pin removed, reinstall carburetor on engine.

Fig 1: Drilling Out Concealment Plug
Courtesy of CHRYSLER GROUP, LLC
Warm engine to normal operating temperature. With headlights, air conditioning (if equipped), cooling fan and all electrical accessories off, check idle speed. Adjust as needed with speed adjusting screw on throttle lever. If equipped with air conditioning, turn system on and adjust "A/C RPM" with screw on side of throttle opener.
Remove air cleaner-to-reed valve hose and plug inlet side of reed valve. Run engine at 3000 RPM for 10 seconds, then allow engine to idle for 2 minutes. Check CO level and adjust to 0.5% using idle mixture screw. Unplug reed valve air inlet and reconnect air hose.

If necessary, reset idle speed with idle speed adjusting screw. Install new roll pin and concealment plug to seal idle mixture adjusting screw. See Fig 2 .

Fig 2: Cutaway View of Tamper-Proof Idle Mixture System

Courtesy of CHRYSLER GROUP, LLC

IDLE SPEED SPECIFICATIONS

Application

Idle RPM

A/C RPM

1400 cc

⁽¹⁾ 650

⁽¹⁾ 850

1600 cc

⁽²⁾ 700

⁽²⁾ 850

2000 cc

⁽³⁾ 700

900

2600 cc

⁽²⁾ 750

900

⁽¹⁾	Add 50 RPM for 4x2-Speed Man. Trans.

⁽²⁾	Add 50 RPM for Auto. Trans.

⁽³⁾	Add 50 RPM for 5-Speed Man. Trans.