FUEL PUMP - TM-55-1740-200-140012

TM 55-1740-200-14

Tension can be adjusted by a knob on top of the brake

1-35. FUEL PUMP. The fuel pump is operated by the

lever.

engine camshaft eccentric directly contacting the fuel

pump rocker arm which in turn actuates the diaphragm.

1-44. ENGINE ASSEMBLY.

The vacuum created by the diaphragm movement pulls

the gasoline from the supply tank, through the inlet valve,

1-45. The gasoline engine (8) is a six-cylinder,

and into the fuel chamber. A fuel filter is an integral part

water-cooled, four-cycle, flat head engine. A positive

of the pump.

displacement, gear-type oil pump forces the engine oil

through an oil filter to lubricate the engine.

1 - 3 6 . CARBURETOR AND GOVERNOR

ASSEMBLY. A single venturi, downdraft-type carburetor

1-46. CRANKSHAFT. The crankshaft is

is installed on the engine. Fuel is supplied through a float

counterweighted and is balanced. The shaft is rifle-drilled

system which consists of a gasoline intake needle, float,

for pressure lubrication of all bearings.

and float chamber. An economizer or step-up system

provides extra fuel for maximum power under full load

1-47. CAMSHAFT. The cast iron alloy camshaft

operation. The carburetor has a manually-operated choke.

incorporates cam lobes for actuating the valve tappets and

an eccentric for operating the fuel pump. The distributor

1-37. A velocity type governor is installed on the

and oil pump are driven by a gear which is an integral

carburetor. Engine speed is governed by the throttle valve

part of the shaft. The chain case cover contains an oil seal

which is closed by the velocity of the fuel-air mixture as

which prevents leakage of oil at the front of the engine.

it passes through the governor. An accurately calibrated

spring system attached to the throttle shaft opposes the

1-48. PISTONS. The aluminum

alloy pistons are

unbalanced air velocity force and controls the position of

attached to the connecting rods by

floating type special

the throttle valve and the maximum speed of the engine.

casehardened piston pins. Each

piston carries two

When in proper operating condition, the governor does

compression rings and two oil rings,

all located above the

not affect engine performance below the speed at which

piston pins.

it begins to control, and does not affect fuel

consumption.

1-49. CYLINDERS. The cylinder block and upper

crankcase are contained in a one-piece casting. The

1-38. COOLING SYSTEM.

cylinder bores are completely surrounded by water jackets

which extend the full length of the cylinder walls. The

1-39. The cooling system (6, figure 1-2) has a tube and

bores are honed to provide the proper piston clearance.

fin-type radiator which cools the engine. Hydraulic

transmission fluid is cooled through the use of separate

1-50. AIR CLEANER. A heavy duty, oil-bath type air

passages in the lower section of the engine coolant

cleaner provides maximum protection against dust, dirt

radiator. A radiator shroud encloses the belt-driven fan.

and abrasives entering the engine through the carburetor.

The cab heater is connected to a hot water pressure

outlet on the water pump. The coolant is returned to a

1-51. HYDRAULIC TRANSMISSION.

cold water suction inlet on the water pump.

1 - 5 2 . The tractor is equipped with a hydraulic

1-40. WATER PUMP. Circulation of the coolant

transmission (9, figure 1-2) sometimes referred to as a

through the engine is accomplished by a centrifugal pump

torque converter, located at the rear of the engine and

mounted at the front end of the engine. The pump is

connected to the engine crankshaft. The unit multiplies

the engine torque, as required, to prevent engine stall, by

driven by a V belt from the engine crankshaft.

adding power during heavy towing operations. It also

1-41 . PARKING BRAKE INSTALLATION.

permits the tractor to move heavy loads with a shock-free

start.

1-42. The parking brake (12) is attached to the output

shaft of the mechanical transmission. It is an external,

1-53. CLUTCH, The hydraulic transmission has an

contracting band type. The band is cam actuated and is

integral hydraulic clutch unit which operates on the same

spring loaded for return to normal position.

filtered fluid as the transmission. The clutch is operated

by a solenoid which is activated by a switch on the

1-43. PARKING BRAKE LEVER. An overcenter

mechanical transmission shift lever. The clutch disengages

parking brake lever, to the right of the operator's seat, is

the transmission drive connection permitting manual gear

connected to the parking brake cam by a control rod.

selection.

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