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3-16
ADJUSTMENTS-REPLACEMENTS
ENGINE FUEL AND EXHAUST SYSTEMS
(90)
indicator mark cut in the flanged edge and an
arrow pointing in the direction of rotation for
a "Lean" setting. Small graduation ribs are
cast in the flange of the choke piston housing
which is integral with the air horn. A larger
rib extending out on this housing serves as an
index point. See figure 3-20.
The thermostatic coil housing is clamped in
position by three retainers and screws which
must be loosened to turn the housing. The
hooked end of thermostatic coil must be in posi-
tion to contact the choker shaft lever and close
the choker valve when coil is cold.
The "Normal" or standard setting of ther-
mostat exists when the indicator mark on coil
housing is in line with the index rib on air
horn. A "Lean" setting is obtained by turning
the coil housing counterclockwise, in the direc-
tion of arrow. A "Rich" setting is obtained by
turning coil housing in the opposite direction.
''1\'
MARK TO COINCIDE
WITH INDICATOR RIB
ON HOUSING
WHEN FASTENING HEAT
PIPE CONNECTION DO
NOT USE EXCESSIVE
PRESSURE TO AVOID
\
CHANGING POSITION OF
\
\
THERMOSTAT COVER
\
\
,,
~lj
Figure 3-21-stromberg Choke Thermostat at Normal Setting
-Series 70
b. Setting of Stromberg Choke Thermostat
An indicator rib is cast on the top surface of
the thermostat housing attached
to.
carburetor
air horn. Small graduation ribs are cast on the
edge of the thermostat cover, and a "V" mark
is .punched on edge of cover to serve as an in-
dex. An arrow cast on thermostat cover points
in the direction of rotation for a "Rich" set-
ting. See figure 3-21.
The thermostat cover is clamped in position
by three lug-washers and screws, which must
be loosened to turn the cover.
It
is also neces-
sary to loosen the heat pipe connection to turn
cover. The hooked end of thermostat coil must
be in position to contact the pin on the vacuum
piston lever and close the choke valve when coil
is cold.
On Series 70, the "Normal" or standard
setting exists when the "V" index mark on
cover aligns with the indicator rib on housing
(fig. 3-21). On Series 40-50, the "Normal" set-
ting exists when the "V" mark is one notch
"Lean" or clockwise from indicator rib.
A "Rich" setting is obtained by turning
thermostat cover counterclockwise, in direction
of arrow on cover. A "Lean" setting is ob-
tained by turning housing in the opposite
direction. When tightening heat pipe connec-
tion do not use excessive pressure, which may
change position of thermostat cover.
3-14 REPLACEMENT OF INTAKE AND
EXH~UST
MANIFOLDS
Exhaust manifolds should never be removed
while the engine is hot because warpage is
liable to occur.
When manifolds are assembled and installed,
care must be exercised to avoid strain which
will result in leaking joints or cracked mani-
folds. Assembly and installation should be done
in the following manner:
1. Install the valve body on the exhaust
manifold with a new ring gasket in pilot ring
recess in body and a new gasket between body
and manifold; make sure that pilot ring is in
place. See figure 3-22. Leave attaching stud
nuts snug but not tight.
f't4--
- VALVE BODY
PILOT RING
Figure 3-22-sectional View of Joints Between Valve Body and
Manifolds
2. Coat joint surfaces with graphite lubri-
cant, then install intake manifold on exhaust
manifold valve body leaving attaching bolts
snug but not tight.
3. Install intake and exhaust manifold as-
sembly on engine with new intake manifold
gaskets. The individual intake manifold gaskets
are centered and the branches of the intake
manifold are aligned with the intake ports in
cylinder head by pilot rings installed at each
joint.
4. Exhaust manifold gaskets are not used.
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