E N G IN E FUEL
6 M - 1 3
M A IN W ELL A IR BLEED
M A IN D ISC H A R G E
N O Z Z L E
BOOST V E N T U R I
M A IN V E N T U R I
POWER PISTON
M E T E R IN G ROD
POWER PISTON
SPRING
M A IN M E T E R IN G
JET
C A L IB R A T IO N
SCREW
POWER PISTON
A C T U A T IN G L IN K A G E
LOWER ID L E A IR B LEED
POWER PISTON V A C U U M
T H R O T T L E V A L V E
MAIN METERING SYSTEM
Fig. 1 7 -Main Metering System
primary air horn, a vacuum break diaphragm unit, fast
idle cam, choke linkage and a thermostatic coil which is
located on the engine manifold. The coil is connected to
the choke valve by a rod. The choke operation is
controlled by a combination of intake manifold vacuum,
the off-set choke valve, thermostatic coil characteristics,
atmospheric tmeperature, and exhaust manifold heat.
The remote thermostatic coil located on the engine
manifold is calibrated to hold the choke valve closed
when starting a cold engine, air velocity against the off
set choke valve causes the valve to open slightly, against
the torque of the thermostatic coil. When the engine is
started, manifold vacuum applied to the vacuum
diaphragm unit mounted on the carburetor air horn will
open the choke valve to a point where the engine will
operate without loading (rich) or stalling (lean). The
choke valve will remain in this position until the engine
begins to warm up.
Through application of exhaust manifold heat, the
thermostatic coil relaxes gradually until the choke valve
is fully open. Opening of the choke valve is controlled by
air flow through the carburetor air horn, past the off-set
choke valve and manifold heat acting upon the
thermostatic coil. As the engine is accelerated during
warm-up, the corresponding drop in manifold vacuum
and low air flow against the off-set choke valve, allows
the thermostatic coil to momentarily close the choke,
providing a richer mixture.
During warm-up it is necessary to provide a faster idle to
prevent engine stalling. This is accomplished by a fast
idle cam which is connected by a rod to a lever on the
choke shaft. The idle screw on the throttle lever contacts
graduated steps on the fast idle cam to provide a faster
idle than normal, to prevent engine stalling during the
warm-up period. When the engine is fully warm and the
choke valve is wide open, the fast idle cam rotates so that
the idle screw rests on the low step on the fast idle cam
where normal curb idle is obtained. Some carubretors
have separate fast and curb idle air adjustment screws. If
the engine becomes flooded during the starting period,
LIGHT DUTY TRUCK SERVICE MANUAL
Summary of Contents for Light Duty Truck 1973
Page 1: ......
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Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
Page 224: ......
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Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
Page 410: ......
Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 492: ......
Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
Page 528: ......
Page 590: ......
Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
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