Buick LeSabre 1965 Service Manual page 104

3 - 2 8 FUEL PUMP
ENGINE FUEL AND EXHAUST
SECTION 3-D
FUEL PUMP
CONTENTS OF SECTION 3-D
Paragraph Subject
3-11 Description and Operation of
Page
Type HE Fuel Pump 3-28
Paragraph Subject Page
3-12 Fuel Pump Inspection and Test . . 3-29
3-13 HE Fuel Pump Repairs 3-29
3 - 1 1 DESCRIPTION AND
OPERATION OF TYPE
HE FUEL PUMP
NOTE: For description and op-
eration information on the 300
engine fuel pump, see paragraph
3-11 of the Buick Special Chassis
Service Manual.
a. Description of Pump
An AC Type HE fuel pump is used
on all engines. The pump assem-
bly is mounted on the right side
of the timing chain cover in an
inverted position, and the pump
rocker arm is actuated by an ec-
centric mounted on front side of
the camshaft sprocket.
The fuel pump has a built-in air
dome with a diaphragm to dampen
out pulsations in the fuel stream.
It is a diaphragm type pump and
is actuated by the rocker arm
through a link and a pull rod. See
Figure 3-22.
b. Operation of Fuel Pump
The fuel pump draws gasoline
from the tank and supplies it to
the carburetor in sufficient quan-
tity to meet engine requirements
under all operating conditions.
The principle parts of the fuel
section are shown in Figure 3-22.
The rocker arm spring holds the
rocker arm in constant contact
with the eccentric on the engine
camshaft sprocket so that the
rocker arm swings up and down
as the camshaft rotates. As the
arm swings downward, it bears
against a shoulder on the link
which is pivoted on the rocker
arm pin. The link swings up-
wards, thereby pulling the fuel
diaphragm upward by means of
the connecting pull rod.
Upward movement of the fuel dia-
phragm compresses the dia-
phragm spring and also creates
a vacuum in the fuel chamber
under the diaphragm. The vacuum
causes the outlet valve to close
and causes fuel from the gasoline
tank to enter the fuel chamber
through the inlet valve.
PUMP BODY-
OIL SEAL
OIL SEAL
RETAINER
LINK
ROCKER ARM PIN
ROCKER ARM
INLET
VALVE
ROCKER ARM SPRING
DIAPHRAGM SPRING
INLET
FITTING
DIAPHRAGM ASSY.
FUEL COVER
VALVE GASKET
-OUTLET VALVE
PULSATOR DIAPHRAGM
-PULSATOR COVER
Figure 3-22—Type HE Fuel Pump