1935 Cadillac - GM Heritage Center

131
GASOLINE SYSTEM
This filler has a double curve where it goes down
from the center of the fender through the side of
the wheel housing, then through the rear floor
down into the tank. The filler is protected from
stones and gravel thrown up by the wheel by a
specially constructed stone guard which is fastened
to the fender and the side of the wheel housing.
On the cars using Fleetwood bodies, the inside
of the filler neck is further protected by a cover
which is bolted to the rear floor and inside of the
wheel housing. A rubber ring is also used in the
wheel housing to keep out dirt.
Service Information
1. Cadillac Carburetor Adjustment
The carburetors used on all Cadillac cars have
only one adjustment, the metering pin, which is
raised or lowered by screwing it into or out of the
fuel orifice. See Plate 48. The metering pin is
properly adjusted when the carburetor leaves the
factory, but if for any reason it should require
adjusting, be sure the engine is well warmed up,
and then adjust the metering pin carefully at idle
speed.
Turning the pin to the right moves the pin
upward into the orifice and makes the mixture
leaner; turning it to the left"increases the orifice
opening and makes the mixture richer.
It is necessary, when adjusting these carburetors,
to make the semi-automatic choke thermostat
inoperative. Simply warming up the engine is not
enough because raising the hood cools the thermostat
enough to apply the choke slightly. If the
connection to the automatic choke thermostat is
blocked in the off position, the choke will be closed,
permitting accurate adjustment.
Whenever the carburetor is to be adjusted,
therefore, the connection to the automatic choke
should be blocked down so that the choke is in
the fully "off" position. After the carburetor has
been correctly adjusted, the adjusting screw
should be turned an additional one-fourth to onehalf
turns to the "'rich - ' side and the choke connectionj'eleasecl.
Another precaution that should be observed in
adjusting these carburetors is to make sure that
the hand choke control is fully released by seeing
that the choke lever on the carburetor is up
against the stop.
Failure to observe these precautions will result
in an overlean mixture, which will invariably
manifest itself in back-firing in the muffler. In
any instances of back-firing, therefore, the first
thing to be done is to readjust the carburetor with
the thermostat blocked open, and the hand choke
fully released.
The
idle speed of the engine should be set by
means of the throttle adjusting screw to a speed
of approximately 320 R. P. M.
After the carburetor has been satisfactorily
adjusted in the idling position to a speed of
approximately 320 R. P. M., the throttle adjusting
screw should be turned slightly more toward
the rich side but not more than of a turn. The
car operates more satisfactorily on a slightly rich
mixture than on a lean mixture, and this additional
x
/i of a turn toward the rich side will help to
prevent any possibility of popping back.
After the throttle stop screw adjustment is
completed the automatic choke connection should
be released. The thermostat should not be
tampered with. It is properly adjusted at the
factory, and ordinarily requires no further adjustment.
If it has been tampered with, however, it
can be adjusted by loosening the adjusting nut and
sliding the thermostat stop until a pull of 12.9
ounces on V-8 cars and 5.2 ounces on V-12 and
V-16 cars is required to hold the thermostat arm
in a horizontal position. This should be done at
a temperature of 70°F.
The carburetor can be correctly adjusted on
the bench before installing it on the engine. The
proper mixture can be obtained by turning the
adjusting screw in the bottom of the carburetor
until it begins to raise the vanes above the aspirating
tube and then backing it out 2¾ turns on
355-D carburetors and 4 complete turns on 370-D
and 452-D carburetors.
The idling adjustment can be made by turning
the throttle stop screw until a .006 in. feeler gauge
on 355-D and a .004 in. feeler gauge on 370-D and
452-D engines will just go between the throttle
butterfly valve and the carburetor body with the
valve in the closed position. The feeler gauge
must not be more than y$ in. in width. The
kicker adjustment is made by setting the choke
lever in the open position and turning the kicker
screw until a .017 in. feeler gauge on 355-D and a
.013 in. feeler gauge on 370-D and 452-D engines
will just go between the throttle butterfly valve
and the carburetor body with the throttle in the
closed position.