GMC 1976 ZEO 6083 Maintenance Manual page 362

6M- 2 0 ENGINE FUEL SYSTEM
6. Float level adjustment :
a. With adjustable T-scale, measure from top
of float bowl gasket surface (gasket removed) to top
of float at toe. Locate gauging point 1/16" back from
toe .
Make sure float retainer is held firmly in place
and arm of float is seated on float needle .
b. Bend float arm as necessary for proper
adjustment by pushing on pontoon. Refer to adjust-
ment chart for specification .
7. Install power piston spring into power piston
well . If primary main metering rods were removed
from hanger, reinstall making sure that tension
spring is connected to top of each rod (figure 15).
Install power piston assembly in well with metering
rods properly positioned in metering jets . Press down
firmly on plastic power piston retainer to make sure
the retainer is seated in recess in bowl and the top is
flush with the top of the bowl casting.
8. Install plastic filler block over float needle,
pressing downward until properly seated .
9. Install pump return spring in pump well .
10. Install air horn gasket around primary main
metering rods and piston . Position gasket over two
dowels on secondary side of bowl .
11 . Install pump plunger in pump well .
AIR HORN ASSEMBLY
If removed, install choke shaft, choke valve and
two attaching screws . Tighten screws securely and
stake lightly in place .
AIR HORN- TO BOWL INSTALLATION
1 . Holding the primary throttle valves wide open,
rotate the air horn assembly so that the pump rod
slides into inner hole in pump lever and then care
fully lower air horn assembly onto the float bowl .
Make sure that the bleed tubes and accelerating well
tubes are positioned properly through the holes in
the air horn gasket . Do not force the air horn assem-
bly onto the bowl, but rather lightly lower in place.
2 . Install two long air horn screws, five short
screws, and two countersunk screws into primary
venturi area. All screws must be tightened evenly
and securely . See Figure 26 .
Figure 26-Air Horn Tightening Sequence
3. Install vacuum break diaphragm combination
rod into the slot in lever on the end of the air valve
shaft. Then install the other end of rod into hole in
the vacuum diaphragm plunger. Install vacuum dia-
phragm assembly to float bowl using two retaining
screws through bracket . Tighten securely .
4. Install rubber hose between the vacuum dia-
phragm and vacuum tube on float bowl .
5 . Connect choke rod into lower choke lever in-
side bowl cavity ; then install upper end of rod into
upper choke lever and retain the choke lever to the
end of choke shaft with attaching screw. Tighten
securely .
NOTE :
Make sure that the flats on the end of the
choke shaft align with flats in the choke lever.
6. Install the secondary metering rods to the sec-
ondary metering rod hanger . The ends of the second-
ary metering rods point inward. Lower secondary
metering rods into float bowl cavity and place hanger
on actuating lever. Install small retaining screw and
tighten lightly and securely .
NOTE :
The thermostatic coil lever inside the
choke housing has to be indexed properly before
installing the choke thermostatic coil cover baf-
fle and gasket assembly . Refer to adjustment
charts (figures 27, 28, 29 and 30) for adjustment
information.
After the inside thermostatic coil lever is ad-
justed, the thermostatic coil, cover and gasket assem-
bly should be installed and rotated counterclockwise
until the choke valve just closes . At this point, the
index cover should be set as shown on adjustment
chart (Choke Coil Adjustment). Install three choke
cover retainers and screws and tighten securely .