Chevrolet 70 1969 Series, Shop Manual

Page: 340 / 913

ENGINE FUEL SYSTEM 6M -13
But under no circumstances should they be inter­
changed with, or replaced by, another type carbur­
etor.
N O T E : For carburetor adjustments on C.C .S.
engines, refer to "Idle and Mixture Adjustments"
previously covered in this section.
V A C U U M ID L E S T O P
(Refer to Fig. 15)
A vacuum idle stop unit is used on all C .C .S.
equipped engines to prevent engine "dieseling”
(engine operation after ignition switch is turned
" O F F " ) .
The idle stop unit is mounted to the carbur­
etor with a bracket and acts upon the throttle plates
of the carburetor in the same manner as an idle
setscrew. When the engine is started, engine vac­
uum acts upon the diaphragm in the idle stop unit
and the plunger is pushed to its full extended posi­
tion. The plunger acts upon the throttle lever and
sets the throttle plates in a position to achieve the
specified idle rpm. When the ignition switch is
turned " O F F ," engine vacuum is reduced and the
plunger retracts into the idle stop unit. The result
is the throttle plate closes to a lower position
which is controlled by the idle speed screw. At
this point, the throttle plate is open only enough to
allow the engine to run well below the normal idle
rpm.
N O T E : For adjustment of the vacuum idle
stop, refer to "Idle and Mixture Adjustment" pre­
viously covered in this section.
SPECIFICATIONS
BENDIX-STROMBERG CARBURETOR MODEL APPLICATION
E X C L U D I N G C A L I F O R N I A V E H I C L E S
T R U C K S E R IE S
E N G IN E
GM P A R T
NO.
V E N D O R
NO.
C O D E
NO.
JM, HM, T M 8 0 .......................................
HM, JM, T M , 8 0 ......................................
4 0 1 M
478 M
2483900
2483900
381167
381167
23-184C
23-184C
(CALIFORNIA VEHICLES ONLY)
T R U C K S E R IE S
E N G IN E
G M P A R T
NO.
V E N D O R
NO.
C O D E
NO.
JM.HM, T M 8 0 .......................................... 4 0 1 M
655923 381257 23-217
H M 8 0 .................................................... 4 01M 655923
381257 23-217
T M 8 0 .................................................... 4 0 1 M
658394 381263 23-223
HM, J M 8 0 ........................... .................. 478M
655923 381257 23-217
T M 8 0 .................................................... 478M
658394 381263
23-223
FUEL PUMP SPECIFICATIONS
PUM P P.S.I.
E N G IN E
M O D E L
P R E S S U R E
V O L U M E
V 6
* A t 1 6 " above outlet.
6440050 5-6 1/2*
1 pint in 20-25 seconds
CHEVROLET ScRiES 70 -80 HEAVY DUTY TRUCK SH O P M A N U A L