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Nissan Stanza/200SX/240SX 1982-1992 Repair Guide

Caurbureted Engines


When the engine is running, the air/fuel mixture from the carburetor is being drawn into the engine by a partial vacuum which is created by the movement of the pistons downward on the intake stroke. The amount of air/fuel mixture that enters into the engine is controlled by the throttle plate(s) in the bottom of the carburetor. When the engine is not running the throttle plate(s) is closed, completely blocking off the bottom of the carburetor from the inside of the engine. The throttle plates are connected by the throttle linkage to the accelerator pedal in the passenger compartment of the vehicle. When you depress the pedal, you open the throttle plates in the carburetor to admit more air/fuel mixture to the engine.

When the engine is not running, the throttle plates are closed. When the engine is idling, it is necessary to have the throttle plates open slightly. To prevent having to hold your foot on the pedal when the engine is idling, an idle speed adjusting screw was added to the carburetor linkage.

The idle adjusting screw contacts a lever (throttle lever) on the outside of the carburetor. When the screw is turned, it either opens or closes the throttle plates of the carburetor, raising or lowering the idle speed of the engine. This screw is called the curb idle adjusting screw.


1982-83 Stanza 49 States Models 1984-85 Stanza Canadian Models

See Figure 1

Always refer to the underhood specifications sticker for any additional applicable procedures.

  1. Connect a tachometer to the engine according the manufacturer's instructions.
  3. Start the engine and run it until it reaches normal operating temperatures.
  5. Operate it at 2,000 rpm for 2 minutes under no load, then idle for 1 minute.

If the cooling fan is operating, wait until it stops.

  1. If equipped with a manual transaxle, place the shift selector in NEUTRAL ; if equipped with an automatic transaxle, place the shift selector in DRIVE .
  3. If the idle speed is not correct, adjust the throttle adjusting screw at the carburetor.
  5. When the idle speed is correct, stop the engine and disconnect the tachometer.

Click image to see an enlarged view

Fig. Fig. 1: Adjusting idle speed -Stanza