Chevrolet 70 1969 Series, Shop Manual

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ENGINE FUEL SYSTEM 6 M -1 1
N O T E : If vacuum gauge is not available adjust
idle mixture screws to give highest idle speed.
Turning idle mixture screws "in” gives leaner
mixture; while turning screws "out" gives richer
mixture. D O N O T turn screws in tight against
seats since screws or seats will be damaged.
7. Reset the engine idle speed to 575 rpm, by
adjusting plunger on vacuum idle stop as previously
described.
8. Turn "in" idle mixture screws (lean mix­
ture) equally to reduce idle speed to 550 rpm.
F L O A T L E V E L A D J U S T M E N T S
W W C Series Carburetor
N O T E : The W W C Series carburetor is used
on the 401M and 478M engines.
Remove air cleaner and disconnect choke
wire from choke lever. Disconnect fast idle link
and accelerating pump rod. Remove three short
screws attaching air horn to main body, then re­
move one long screw at forward side of air horn
and one long screw next to fuel body. Replace
these screws with two of the screws to hold main
body flange to throttle body, tighten securely.
Remove balance of air horn to main body screws,
then remove air horn.
Use float gauge (J-8824) to check relationship
of the float to the top of the fuel bowl as typically
shown in Figure 12. The gauge has several stops
for use with various carburetors. Refer to
"Specifications" for proper float level adjustment
Bending Tool
Float
* . . / j
jmmmjfr A
BENDING LEVER TO RAISE SETTING
Bending Tool
Float
BENDING LEVER TO LOWER SETTING
Bending Tool
Float
Figure 13— Use of Bending Tool to Set Float Level
CHEVROLET SERIES 70 -8 0 H EAVY DUTY TRUCK SH O P M A N U A L