ARMY TM 9-2815-257-24 AIR FORCE TO 38G1-128-2 MARINE CORPS TM 10155A/2815-24/3 2-1 CHAPTER 2 OPERATING INSTRUCTIONS Section I   PRINCIPLES OF OPERATION..............................................................................2-2 2-1 Principles of Operation ............................................................................................2-2 2-2 Engine Starting System............................................................................................2-2 2-3 Engine Combustion Cycle .......................................................................................2-2 2-4 Engine Lubrication ..................................................................................................2-4 Section II OPERATING INSTRUCTIONS .............................................................................2-4