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Home >> Mazda >> 1981 >> B2000 Sundowner >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Deceleration Control System >> Testing & Adjustment >> Throttle Positioner System >> Servo Diaphragm
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Servo Diaphragm

  1. Connect tachometer to engine. Start and warm engine to normal operating temperature. Stop engine. Remove air cleaner.
  2. Detach intake manifold vacuum hose from 3-way solenoid and detach 3-way solenoid vacuum hose from servo diaphragm. Connect intake manifold vacuum hose directly to servo diaphragm.
  3. Start engine, run at 2000 RPM, then decrease to idle. With servo diaphragm connected directly to intake manifold vacuum, engine should idle at RPM shown in Throttle Positioner System Operating RPM table.
    NOTE: If vehicle is equipped with air conditioning, engine should idle at 1100-1300 RPM with air conditioning operating.
  4. If speed is not to specification, turn throttle positioner adjusting screw located on linkage near end of servo diaphragm link on carburetor. If specification cannot be obtained, replace servo diaphragm.
    Throttle Positioner System Operating RPM

    Application (1)RPM
    B2000
      Federal 900-1100
      California 1000-1200
    All Others 1100-1300
    (1) Auto. Trans. in Neutral.
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