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Home >> GMC >> 1982 >> Magnavan Automatic Trans, Trans Mfr CD 475/M40 >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> ROCHESTER Models M4MC & M4ME 4-Barrel >> Adjustment >> Accelerator Pump

Accelerator Pump

  1. Close throttle valves completely. Make sure fast idle cam follower is off fast idle cam steps. Bend secondary throttle closing tang to fully close primary throttle valves. Readjust after accelerator pump adjustment.
    Fig 1: Accelerator Pump Adjustment
    G09360543Courtesy of GENERAL MOTORS COMPANY

    Make sure fast idle cam follower is off fast idle cam steps. 

  2. Make sure accelerator pump rod is in specified hole (inner or outer) of accelerator pump lever.
  3. Using a "T" scale, measure specified distance from top of choke valve wall (next to vent stack) to top of pump stem.
  4. To adjust, bend accelerator pump lever at point shown in Fig 1.