TM  5-2815-241-34&P FUEL PUMP CALIBRATION - CONTINUED ACTION LOCATION ITEM REMARKS PUMP  MAIN  PRESSURE  TESTING  AND  ADJUSTING 31. Test  stand  (1) Test and adjust pump main pressure as follows: a. With  vacuum  set  at  &inch  (203.2  mm) HG  on  no.  2  vacuum  gage  (2)  and  throt- tle  lever  (3)  wide  open,  adjust  speed  to 2100  rpm. b. Place  selector  valve  (4)  to  ROTAMETER position. c. Set fuel flow to 315 pph with fuel flow control  valve  (5). Fuel  pressure  should  be  172  to  178  psi (1188 to 1227 kPa). d.  If  172  to  178  psi  (1186  to  1227  kPa)  fuel pressure does not read on pressure gage (6) adjust pressure. FUEL  PRESSURE  TESTING  AND  ADJUSTING CAUTION Be careful not to damage bore of throttle shaft when drilling out ball. NOTE Throttle shaft internal adjusting screw is covered by a soft steel ball in end of throttle shaft, and must be removed if not previously removed. Perform step 32 only if ball has not   been   previously   removed. 32.  Fuel  pump  (7) throttle shaft (8) Ball  (9) Using center punch, 1/4-inch drill bit, and 3/8-inch  portable  electric  drill,  drill  out ball. 33.  Test  stand  (1) Fuel  pump  (7) throttle shaft (8) Test and adjust fuel pressure as follows: Set  fuel  pressure  to  172  to  178  psi  (1186  to 1227  kPa). Screw  Internal  fuel  adjusting  screw  In throttle  shaft  in  to  Increase  pressure, or  out  to  decrease  pressure. 2-346