TM  10-3930-638-24&P 3-5. ENGINE MAINTENANCE (cont) a. Engine Tune-up (cont). (3)  Fuel  Injection  Pump  Adjustments  (cont). STEP LOCATION ITEM ACTION REMARKS ENGINE  IDLE  SPEED  ADJUSTMENT  (cont) NOTE 2 (cont) Tachometer drive shaft operates at one half engine speed. Double tachometer reading to obtain engine RPM. c. Engine idle speed Measure Repeat step b above to recheck idle speed. If engine idle speed is 825-850 RPM, proceed to step 3. If idle speed is not correct, proceed to step d. d. Idle speed screw Check  position With  accelerator  pedal  at  idle  position, check if idle speed screw is against the injection pump boss. M screw is not against pump boss, adjust accelerator cable ball joint (para 2-15i). If idle screw is  against  pump  boss,  proceed-to  step  e below 3-35