Pontiac tempest 1968 Service Manual page 325

6B-18
1968 P O N T I A C SERVICE MANUAL
Whenever solenoid screw is turned to adjust idle,
the throttle should be opened slightly, then closed to
seat throttle lever extension on the screw.
The idle mixture should be adjusted to give best
lean idle at specified idle speed. Missing is a sign of
too lean an idle mixture while rolling or loping indi­
cates too rich a mixture. Turning idle mixture screw
in, leans out mixture; four turns out from lightly
seated position may be used as a preliminary setting
of mixture screws; mixture to be leaned out from
this setting to achieve best lean idle.
PERIODIC SERVICE
There are no periodic services required on the
Rochester 2GV carburetor; however, choke linkage,
choke valve and levers and pump linkage should be
kept free of dirt and gum so that they will operate
freely. DO NOT OIL CHOKE V A L V E SHAFT OR
ANY PART O F THE LINKAGE.
OVERHAUL AND ADJUSTMENT
V A C U U M
BREAK UNIT
•
C H O K E
C O I L R O D - ^ "
4 \
FUEL INLET
- C H O K E THERMOSTAT
Flooding, stumble on acceleration and other per­
formance complaints are, in many instances, caused
by presence of dirt, water or other foreign matter
in carburetor. To aid in diagnosing the cause of
complaint, the carburetor should be carefully re­
moved from engine without draining fuel from bowl.
The contents of fuel bowl may then be examined for
contamination as carburetor is disassembled.
The following is a step-by-step sequence by which
the Rochester 2GV carburetor may be completely
disassembled and reassembled. Adjustments may be
made and various parts of the carburetor may be
serviced without completely disassembling the entire
unit.
DISASSEMBLY OF BOWL COVER
1. Remove fuel inlet filter retainer nut and gasket
and remove filter.
2. Disconnect pump link (Fig. 6B-40) from pump
lever by removing spring clip. Remove lower end of
pump rod from throttle lever by removing clip.
3. Detach choke intermediate rod (Fig. 6B-39) at
lower end by removing clip, then detach choke
intermediate rod from choke shaft by rotating until
tang on rod clears slot in lever.
4. Remove retaining screw at end of choke shaft
and remove choke trip lever and fast idle link and
lever (Fig. 6B-40). Lever can be removed from link
by turning until slot in lever will pass over tang on
link. The link and fast idle cam are retained by a
Truarc washer. Disassembly of these pieces will
destroy Truarc washer.
Fig. 6B-39 Rochester 2 G V Carburetor
5. Remove eight cover screws and lift cover from
bowl (Fig. 6B-41).
6. Remove vacuum break unit and hose.
7. Place unended cover on flat surface. Remove
float hinge pin and lift float from cover (Fig. 6B-42).
Float needle may now be removed from seat.
8. Remove float needle seat, screen (Fig. 6B-42)
and gasket with wide blade screwdriver.
C H O K E
R O D
G A U G E
N O T C H '
FAST IDLE LEVER
/
IDLE MIXTURE NEEDLES
Fig. 6B-40 Rochester 2 G V Carburetor