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Home >> Plymouth >> 1981 >> Arrow Pickup Base, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Vacuum Throttle Positioner >> Adjustment
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Vacuum Throttle Positioner: Adjustment

  1. Start engine and accelerate to about 2000 RPM. Verify throttle positioner operation. Throttle positioner must withstand hand pressure. Manually open throttle until engine speed reaches approximately 2000 RPM. Loosen lock nut and adjust throttle positioner until it just contacts throttle lever.
  2. Release throttle lever, then slowly adjust positioner until a sudden drop in speed occurs (over 1000 RPM). At this point, continue adjusting positioner in a decreasing direction for an additional 1/4 of a turn and tighten lock nut. Accelerate engine to approximately 2300 RPM and release throttle. Engine should return to normal idle speed.