ARMY TM 9-2805-256-14
AIR FORCE TO 38G2-102-2
NAVY NAVFAC P-8-611-14E
1-12. Differences Between Models. All four models of the Military Standard are the same except for the
Models 1A08-1, -2 are equipped with wet air cleaners. Models 1A08-3, -4 have dry air cleaners with service
Models 1A08-1, -2 are equipped with STOP buttons.
Models 1A08-3, -4 are equipped with ignition switches.
Model 1A08-4 has a breakerless ignition system. Models 1A 08-1, -2, -3 have a breaker point system with
Models 1A08-3, -4 are equipped with throttle controls.
1-13. Safety, Care, and Handling. Observe all WARNINGS, CAUTIONS and NOTES in this manual. This
equipment can be extremely dangerous if these instructions are not followed.
Section Ill. PRINCIPLES OF OPERATION
1-14. Principles of Operation.
a. G e n e r a l. The 1 1/2 Hp Military Standard engine is a four cycle single cylinder, air cooled, gasoline powered
internal combustion engine. The engine develops its full rated capacity at a governed 3600 r.p.m.
A starter flange, on the flywheel fan, provides a means to connect the
starter rope for pull starting the engine. An inline fuel filter cleans the fuel supplied to the engine. The filter comes
equipped with a fuel cutoff valve, that when closed, stops fuel flow to the engine. The engine comes equipped
with either an oil bath or a dry element air cleaner. Both types of air cleaners provide the same amount of filtering,
but the dry element air cleaner has two unique features, a built in service indicator and an air inlet control. The
service indicator signals when the element requires cleaning. The inlet temperature control varies the amount of
unheated air entering the air cleaner. On models 1A08-1 and -2 a stop button is used to terminate engine
operation. On models 1A08-3 and -4 a two position ignition switch is used. When the switch is in the RUN
position the engine can be started. Setting the switch to OFF terminates engine operation
c. Detailed Principles of O p e r a t i o n.
(1) Fuel system. The fuel system is composed of a fuel filter, fuel pump, fuel line, and carburetor. The fuel
filter is a bowl type with a filtering screen. The screen filters dirt and other foreign materials from the fuel. The
fuel pump drains fuel from an external fuel supply through the fuel filter, and delivers it to the carburetor. The fuel
pump, a diaphragm type, is driven by the camshaft. The fuel pump can be operated manually, using the priming
lever. This allows the fuel system, between the pump and the carburetor, to be primed before starting the engine.
The carburetor mixes the air, from the air cleaner, and the fuel. This is then delivered to the combustion chamber
where it is compressed and burned.
(2) Cooling system. The flywheel fan draws cool air into the flywheel fan cover, where it is then directed by
the cylinder head covers, and oil pan cover. The air flows around the cylinder and cylinder head assembly and
cools the engine.