Buick LeSabre 1965 Service Manual page 85

ENGINE FUEL AND EXHAUST SYSTEMS
DESCRIPTION 3 - 9
3 - 2 DESCRIPTION OF FUEL
SYSTEM
a. Gasoline Tank, Feed Pipe,
and Filter
The gasoline tank is attached to
the under side of the trunk floor
pan. The tank is attached with two
straps which have a hook at one
end and are bolted at the other
end.
The socket for the gas tank filler
is soldered into an opening at the
rear upper center of the tank. The
lower end of the filler slides
through an "O" ring seal and is
held in position by a bracket and
screw near the upper end. The
tank is vented at a special pipe
rather than at the filler cap. This
breather pipe extends from the
upper center of the tank and has
a rubber hose extending from it
to an i n v e r t e d U-shaped pipe
fastened into the body. A positive
sealing filler cap is used.
The tank outlet is located at the
upper front center of the tank. It
consists of a combination fuel
pick-up, filter, and gas gauge tank
unit. The tank unit can be r e -
moved without lowering the gas
tank by removing a cam ring
which retains the unit (all except
Rivieras).
The fuel line is w e l d e d steel
tubing with a terne coat outside
and a tin coat inside. Connections
from the tank to the line and from
the line to the fuel pump are made
with synthetic r u b b e r hose at-
tached with spring clamps.
A can-type throw-away fuel filter
is located in the line between the
fuel pump and the carburetor.
In all air conditioner equipped
cars, a vapor by-pass system is
installed. These c a r s have a
special fuel filter which has a
metering outlet in the top. Any
vapor which forms is bled off and
returned to the gas tank through a
separate line alongside the fuel
supply line. This system greatly
reduces any possibility of vapor
lock. See Figures 3-1, 2 and 3.
b. Fuel Pump, Carburetor, and
Automatic Choke
The fuel pump is mounted on the
lower right side of the timing
c h a i n cover. It is actuated
by a h a r d e n e d , chrome-plated,
stamped steel eccentric mounted
on the front side of the crankshaft
sprocket. The pump is inverted,
thereby placing it in a lower,
cooler location. It has a built in
air dome with a diaphragm to
dampen out p u l s a t i o n s in fuel
pressure. The construction and
operation of the pump are de-
scribed in Section 3-D.
c. Air Cleaner and Intake
Silencer
All engines (except dual 4-barrel
engines) are equipped with oil
wetted polyurethane foam element
air cleaners combined with intake
silencers. The air cleaner r e -
moves abrasive dust and dirt
from the air before it enters the
engine through the carburetor.
The intake silencer reduces to a
very low level the roaring noise
made by the air as it is drawn
through the intake system. The
cleaner and silencer also func-
tions as a flame arrester in event
of "backfire" through the intake
system.
There are three basic air cleaner
and silencer assemblies: one for
two barrel carburetor cars, one
for four barrel carburetor cars,
and one for dual four barrel car-
buretor cars. See Figure 3-5.
Standard four barrel carburetor
air cleaners have two locating
tabs which engage two projections
on the carburetor air horn to
locate the large air inlet tube
firmly in position about 15° to the
right of the centerline of the
engine.
Two barrel c a r b u r e t o r air
cleaners have neither a support
bracket nor locating tabs. There-
fore it is important to securely
tighten the wing nut by hand after
locating the air cleaner on the
carburetor to make sure the
air cleaner remains stationary.
Proper location is with the intake
pointed about 45° to left of the
centerline of the engine and with
the word "FRONT" on the air
cleaner forward.
The air cleaner (except for dual
4-barrels) has a washable plastic
foam type element. It consists of
a cylinder of polyurethane foam
over a perforated sheet metal
supporting screen. This screen
also acts as a flame arrester in
case of a backfire. Dual 4-barrel
air c l e a n e r s have a disposable
dry type fiber element.
d. Carburetor Throttle Control
Linkage
The carburetor throttle control
linkage is designed to provide
positive control of the throttle
valves through their entire range
FOR 401 AND 425 ENGINES
FOR DUAL 4-BARREL
Figure 3-5—Air Cleaners and
Silencer Assemblies