TM 9-2815-225-34&P 3-63.  FUEL PUMP TESTING AND CALIBRATION (Contd) LOCATION/ITEM ACTION REMARKS d.  Fuel Pump Run-in (Big Cam I and Big Cam III) (Contd) 42. Power switch on test stand Turn to ON position. Power "ON" light (21) should light (1) up. 43. Fuel heat switch (19) Turn to ON position and observe Fuel heat "ON" light (18) should fuel temperature on fuel light up.  Proper operating temperature gauge (4). temperature for calibration fluid is 90-100F (32.2-37.8C).  The test stand (1) built-in thermometer will automatically maintain this temperature once the fluid has been circulated. 44. Pressure regulator (9) Adjust until a reading of 50.00 Hg (180,000 kPa) registers on pressure gauge (8). 45. Start button (26) Depress to start test stand (1). 46. Fast switch (25) Depress and release as necessary and slow switch (23) until exactly 500 rpm is indicated on tachometer (7). NOTE Check the flowmeter glass tube for air in the fuel flow.  If air bubbles are present, work the fuel pump throttle lever from full-open to idle several times to relieve any trapped air in the pump.  If air bubbles persist, it is an indication of an air leak in the system.  Turn the test stand off and check all line connections between the test stand and fuel pump for tightness. Check the rating of gear pump to main housing and check to see that test stand reservoir is full of fluid. 3-482