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ENGINE FUEL AND EXHAUST SYSTEMS
ADJUSTMENTS-REPLACEMENTS
3-13
A
-+-+--8
r->t-·~·
~ H EAT
OFF
Figure 3-16-Valve Anti-Rattle
Spring Adlustnrent
3-12 CARBURETOR ADJUSTMENT
Do not attempt to adjust the carburetor idle
needle valves until it is known that the ignition
system is in proper operating condition (par.
10-44), that compression is satisfactory and
valves are properly adjusted. It should also be
known that the exhaust manifold valve is
operating properly (par. 3-11) and that intake
manifold has no air leaks, that gasoline filters
and strainers are clean (par. 3-9), that fuel
pump is supplying carburetor with ample fuel
at specified pressure (par. 3-17), that the air
supply is not restricted by the air cleaner (par.
3-8) or choke
(par.
3-13) and that throttle con-
trol linkage is correctly adjusted (par. 3-10).
Any attempt to adjust or alter the carburetor
to compensate for faulty conditions elsewhere
in items affecting engine performance will
result in reduced fuel economy and overall
performance.
a. Checking Float Bowl Fuel Level
Any deviation from the specified fuel level
in the float bowl will seriously affect carbure-
tion; therefore, the level should be checked
before adjusting the carburetor.
1. Remove the fuel level sight plug from car-
buretor float bowl.
c. Adiustlng
Valve Anti-
Rattle Spring
The anti-rattle
spring shown at
"A" in figure 3-16
must be adjusted
so that the valve
cannot flutter and
chatter against the
inside of valve
body in either the
closed (heat on) or
open (heat off) po-
sitions. These positions can be felt by moving
the counterweight by hand, and adjustment can
be made with engine hot or cold.
Bend clip "C" as required so that spring "A"
will prevent the valve from contacting the valve
body in either closed or open positions. Adjust-
ment so that valve has sufficient clearance to
prevent rattle in the closed position will usually
be correct for the open position also. Clearance
equal to
Vt
6"
to
Va"
movement at the extreme
end of counterweight is
correct.
a. Freeing Up Sticking Valve
Carbon or lead salt deposits around the valve
shaft may cause the valve to stick or become
sluggish in operation. A valve sticking in the
open position will cause slow engine warm up,
excessive spitting and sluggish engine opera-
tion when cold. A valve sticking in the closed
position will cause overheating, loss of power,
and hard starting when the engine is hot, and
may also cause warped or cracked manifolds.
Sticking in either position will adversely affect
fuel economy.
If the valve shaft is sticking or frozen in
the valve body, free it up by tapping on the
ends with a light hammer, and by rotating the
counterweight. Penetrating oil or kerosene may
be used to aid in freeing the shaft.
When the valve shaft is free, apply a mixture
of kerosene and powdered graphite liberally to
the shaft bearing; the mixture to be composed
of 21j2 ounces of powdered graphite to 1 pint of
kerosene. Lubrication of shaft every 1,000
miles is specified in Lubricare Instructions
(par. 1-1).
b. Checking Manifold Valve Thermostat
Setting
The setting of the exhaust manifold valve
thermostat may be checked when the engine is
at room temperature of approximately 70° F.
Unhook ,t he outer end of thermostat from
anchor stud on the valve body and hold the
valve in: the closed (heat on) position. To bring
the end of thermostat to the anchor stud will
then require approximately lA, turn wind-up of
the thermostat.
.
The thermostat is not adjustable and should
never be distorted or altered in any way as this
will affect its calibration. If the thermostat
does not have the proper setting, or is dam-
aged, it should be replaced.
3-11 EXHAUST MANIFOLD VALVE
.
SERVICE
unloader does not operate properly, adjust as
described in paragraph 3-23 (Carter) or 3-30
(Stromberg) .
4. Hold choke valve closed and check clear-
ance beween the fast idle cam and the adjust-
ment or stop screw. Clearance should be
%4"
to
Y32", and may be obtained by adjusting the
screw on the dash pot operating lever at lower
end of equalizer shaft. See figure 3-15.
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