Datsun 1000 Workshop Manual page 42

9 Fuel
Syatem
2 1
DESCRIPTION
The fuel
pump is
a
mechanically operated diaphragm
type
actuated
by
a
rocker
arm
assembly which in
turn
is
operated by
an eeCCll
tTic
on
the engine
camshaft
When
the carhurettor floar chamber
is
full
and
the
carburettor needle valve
is closed pressure in the pump
outlet pipe will hold
the
pump
diaphragm downwards
against
the pressure
of
the
diaphragm spring
At this time the rocker
arm
assembly
will
run
freely
on
the
diaphragm
stem
until the pressure in the outlet
pipe
is
relieved
When the outlet
pipe
pressure
is
relieved
the
pump
diaphragm again
rises under pressure from
the
diaphragm
spring
and into
operation by
the rocker
ann
assembly
A small
compression spring
holds
the rocker
ann
in
constant
contact
with the eccentric
on
the
camshaft
to
minimise
operating
noise
A
seal which
runs
on
the
diaphragm
stem
and which is
retained in the fuel pump lower
body by the
diaphragm
spring prevents engine
oil
from
entering
the upper section
of
the pump
lower
body
The rubber fuel
pump
diaphragm is held
together by
two
metal discs and
is
specially
treated
so
that it is
not
affected
by gasoline
TO
REMOVE
AND INSTAL
I
Raise the
engirie bonnet
and
fit fender
covers to
both front fenders
2 Disconnect the fuel inlet
and outlet
pipes
at
the
fuel
pump
connections
OUTLET
VALVE
lIP
1 Remove
the
two
nuts
and
spring
washers which
secure
the
fuet
pump
to
the
cylinder
block
and withdraw
the fuel
pump with
spacer
and
gaskets
NOTL
During operation
3 lousen the
luts
progressiFeh
until pressure
nf
the
diaphragm and
rocker
aml
spring
is
reUelled
I n st a l l Jti o n
is
a
reversal
of the removal
procedure
with
attention
given to
the
following
Instal
new
gaskets
to
both
sides
of
the fuel pump
spacer
PUMP
OUTLET
RETAINING SCREW
Assembled View of Fuel
Pump
RETAINER
DIAPHRAGM MOUNTING FACE
FUEL NLET
t
INLET VALVE
Valves Mounted in Fuel
Pump Upper Body
42