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3-14
ADJUSTMENTS-REPLACEMENTS
ENGINE FUEL AND EXHAUST SYSTEMS
(88)
FUEL
LEVEL
~
P LUG
Figure 3-17 -Float Bowl Fuel Level
2. With engine idling at normal operating
temperature, the fuel in the bowl must be just
high enough to wet the threads at the lower side
of the sight hole. See figure 3-17.
3. If the fuel level is not correct, it must be
adjusted to correct height to insure proper car-
buretor operation. If the level is too high it is
advisable to check fuel pump pressure (par.
3-17) before making an adjustment of car-
buretor float.
b. Making Initial Setting of Throttle
Stop Screw
The initial setting of the throttle stop screw
will provide an engine idling speed of approxi-
mately 450 RPM (8 MPH on level road in third
speed) to prevent stalling during starting and
warm up of engine.
1.
Back off throttle stop screw until throttle
valves are fully closed.
2.
With choke wide open, turn throttle stop
screw "IN" (clockwise) until it just contacts
the low step of fast idle cam of Stromberg car-
buretor or boss on throttle body of Carter car-
buretor.
3. Turn throttle stop screw "IN" one com-
plete turn, which will give engine idling speed
of approximately 450 r.p.m.
NOTE: If the engine operates on fast idle
too long after starting or else moves to slow
idle too soon, or the choke unloader does not
operate properly, check fast idle cam and choke
unloader adjustments as described in paragraph
3-23
(Carter) or paragraph 3-30 (Stromberg).
c. Making Initial Setting of Idle
Needle Valves
An initial setting of the idle needle valves is
necessary to make certain that both valves are
opened an equal amount.
1.
With engine stopped, turn both idle needle
valves "IN" (clockwise) until they seat lightly.
CAUTION: Do not force valves against seats
as this will damage valves and seats.
2. On Stromberg carburetor, turn each valve
"OUT" (counter clockwise) I%, turns. On
Carter carburetor, turn each valve "OUT" 1
turn. Be careful to turn both valves exactly the
same amount. See figure 3-18.
d. Making Final Adjustment of Idle
Needle Valves
The two idle needle valves and the throttle
stop screw are the only external means pro-
vided for adjusting the carburetor. Turning the
idle needle valves "IN" (clockwise) makes the
mixture "LEAN."
The idle needle valves control the idle or low
speed system of the carburetor; all adjustments
affecting the main metering or high speed
system are made during assembly of the car-
buretor.
Figure 3-1 a-Initial Setting of Idle Needle Valves
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