Chevrolet 10 Series 1970, Руководство по обслуживанию

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ENGINE FUEL 6M -7
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BATTERY
DISTRIBUTOR CARBURETOR
BUTTFRFLY VALVE
SPINNER VALVE
IG N IT IO N
SW ITCH
AMBER
LAMP
LAMP BURN-OUT CH EC K IN G CIRCUIT
OIL PRESSURE
SW ITCH
ENGINE OVER-SPEED WARNING SYSTEM
CARBURETOR ACTUATOR
F ig . 2 g —G o v e rn o r and O verspee d W a rn in g L ig h t S c hem atic
not actually fo rc e the throttle va lve open but rather a l­
low s them to fo llo w the throttle le v e r because of the
go v e rn o r spring tension. Thus when the throttle le v e r is
m oved to wide open position, the position o f the throttle
va lv e w ill be determ ined by vacuum on the diaphragm and
the tension o f the go vern o r o r spring acting on the g o v ­
ern o r le v e r .
Vacuum is applied to the diaphragm through a system
o f vacuum passages and res tric tio n s in the throttle body
and go vern o r housing.
A speed sen sitive centrifugal
va lve in the distribu tor acts as a vacuum break so that
there is no vacuum applied to the diaphragm until the
d e s ire d governed speed is reached. When the governed
speed is reached the va lve is closed and vacuum is ap­
p lied to the diaphragm which acts to c lo se the throttle
va lv e s in opposition to t h e g o vern or sprin g tension.
When pow er is requ ired as load is in creased , engine rpm
w ill drop causing d istrib u tor valve to open and allow the
go vern o r spring to open the throttle v a lves further.
MAJOR SERVICE OPERATIONS
CONTRO L VALVE
W henever the d istrib u tor is rem oved fo r overhaul, the
g o v e rn o r control va lve m echanism should be d isa ssem ­
bled and cleaned (See Engine D istrib u tors in Section 6Y).
G O VER N O R H O U SIN G
Removal
1. R em ove the four g o vern o r c o v e r attaching screw s
and then the go vern o r c o v e r and gasket i f used (fig .
3G).
2. Detach and rem ove the g o vern or spring.
3. Rem ove the eight diaphragm co v e r attaching screw s
and then the diaphragm c o v e r. Hold the throttle
le v e r to avoid damage to the throttle v a lves and
loosen the nut attaching the go vern o r le v e r and pin
assem bly to the throttle shaft. R em ove the govern or
le v e r fro m the throttle shaft, then detach it fro m the
diaphragm rod by rotating the le v e r until the tang on
the rod c le a rs the slo t in the le v e r.
4. R em ove the diaphragm assem bly fro m the housing
and inspect fo r cracks o r holes. If the diaphragm is
damaged in any way, it must be replaced.
5. R em ove the three govern or attaching screw s, then
rem ove the leath er seal reta in er and leath er seal.
6. Detach the go vern o r housing fro m the throttle body.
7. The throttle le v e r and bearin g assem bly can be r e ­
moved by detaching the fast idle cam and pump rod
and rem oving the four attaching scre w s . No attempt
should be made to s e r v ic e the throttle le v e r bearing.
If the action indicates excessive fric tio n to the point
that the throttle return spring cannot o verco m e
the binding, the throttle le v e r assem bly should be
replaced.
CAUTIO N: Since the id le ports in the throttle
CHEVROLET TRUCK SERVICE MANUAL