1935 Cadillac - GM Heritage Center

133
GASOLINE SYSTEM
right-hand throttle control rod very carefully, so
that the pin will slip into place without affecting
the throttle opening on either carburetor. This
adjustment must be made very accurately so
as not to disturb the throttle equalization. While
testing the car on the road the above adjustments
should be rechecked to be sure they are
satisfactory.
3. LaSalle Carburetor Adjustment
LOW SPEED OR IDLING
ADJUSTMENT
Before making this adjustment the engine should
be warmed up and the manifold and windshield
wiper connections made tight. The idle speed of
the engine should be set by means of the throttle
stop screw to a speed equivalent to about 6 miles
per hour. The idle needle valves control the
gasoline for low speed adjustment. Turning the
•needles out gives a richer mixture, and turning
them in gives a leaner mixture. See Plate 50.
Taking one side of the carburetor at a time, turn
the inner needle valve (the one toward the engine)
in slowly until the engine begins to lag or run
irregularly, then slowly turn it out until the engine
begins to roll. Finally, very slowly, turn in the
adjustment again just enough so that the engine
runs smoothly for this throttle opening. This
adjusts the mixture to the four cylinders which
are fed by the inner barrel of the carburetor.
Adjust the outer needle valve so that the other
four cylinders fed by the outer barrel, or the one
away from the engine, fire smoothly. It may be
necessary after completing this adjustment to
decrease the engine speed slightly.
To check the thermostat in the automatic choke
FUEL LEVEL
control, it is necessary to remove the complete
Accurate float level setting is particularly thermostat unit, Fig. 11, Plate 50, from the
essential to satisfactory starting when the engine manifold and proceed as follows, using a master
is hot. The level is set at the factory at Y% in. thermostat gauge, Part No. 1406781, as a guide.
below the top surface of the float bowl as shown 1. Unhook the thermostat spring from the
in Fig. 12, Plate 50. In other words, the level of prong on the indicator.
the fuel in the float bowl should be % in. below 2. Move the thermostat lever to the stop
the top edge of the bowl, measured with the bowl nearest the top mounting screw hole and measure
cover removed. This setting may be changed if the distance from the center line of this hole to
necessary by bending the float arm where it meets the center line of the hole in the arm.
the float, up or down to give the desired position.
This distance should be exectly y^-'mch as
To check the float level proceed as follows:
Disconnect the secondary ignition wire at the
coil. Remove the upper part of the carburetor,
which includes the float chamber cover, after
disconnecting the choke rod and throttle pump
rod.
Draw enough gasoline out of the float chamber
to permit the needle valve to open.
Lay a flat piece of metal over the float chamber
and throttle pump passage, but with the main air
intake uncovered, and crank the engine for two
or three seconds with the starter, to refill the
float chamber to its normal operating level.
The level should then he measured in the
throttle pump passage, as due to the normal tilt
of the engine and carburetor the level is highest
at this point.
While the float chamber cover is off, the needle
valve should be inspected to make sure that it
does not bind on its seat. Replacement of firsttype
needle valves and seats with second-type
parts, is recommended on early cars where correction
of the float setting does not give satisfactory
starting.
The difference between the first-and secondtype
parts is in the diameter of the float needle
valve seat. First-type seats have a diameter of
.130 inch and second-type seats a diameter of .093
inch. This smaller size seat gives a more constant
fuel level in the float chamber and reduces likelihood
of carburetor "loading" or hard starting
when the engine is hot.
Only second-type needle valves and seats are
available and are supplied by the Parts Division
as a unit under Part No. 1409270.
FAST IDLE ADJUSTING SCREW
Before adjusting the fast idle adjusting screw,
Fig. 11, Plate 50, the throttle stop screw should
be adjusted for the proper idling speed with the
engine warm. The fast idle adjusting screw is
next screwed down or turned in to contact with
the low flat or small diameter on the cam with
the choke valve fully open and then screwed out
about turn so as to allow a .010 in. clearance
between the end of the adjusting screw and this
cam diameter.
4. Thermostat Setting
indicated in Fig. 13, Plate 50. If it is more or
less, loosen the retaining screw and bring the lug
on the hub of the thermostat against the thermostat
lever to locate this position and tighten the
retaining screw securely.
3. Use a piece of twine or a rubber band to hold
the arm in this position. Do the same with the
master thermostat.
4. Immerse both thermostats in water and let
them remain for at least one minute to equalize
their temperatures. The exact temperature of
the water is not important, although it should
approximate room temperature to avoid rapid
changes when removed for adjustment.