CHAPTER
2
TI{E
FUEL
SYSTEM
2:1 Fuel
pump,
operating
principles
2:2 Routine
maintenance
2:3 Removing and dismantling the
fuel
pump
2:4 Reassembling the fuel
pump
2:5 Testing the
fuel
pump
2:6
Carburetter,
Solex PBICA
2 :1 Fuel
pump,
operating
principles
All the
XC series engines use a mechanically operated
diaphragm
type Íuel
pump
which may be manuÍactured
by either
AC, Guiot or
SEV.
They are all very srmilar in
construction and operation, and
the instructions
given
in this
Section
for
the AC may be easily adapted to suit
the other two
makes. An
exploded
view
of the
fuel
pump
is
shown
in FIG 2 :1 .
The rocker
arm,
actuated
by
the
camshaft, moves
the
diaphragm up and down. When the diaphragm
is
down,
fuel is
drawn
into the
pump
via the inlet valve.
On
the
upward movement oÍ the
diaphragm
the inlet valve
is
closed, the outlet
valve
opens and
f
uel
is
pumped
through the outlet
pipe
to the carburetter.
2:2 Routine maintenance
To clean the
filter
screen, detach
the main fuel
pipe
hose
from the
pump
and
plug
the hose to
prevent
fuel
loss. Remove the bowl and
lift
oÍf
the screen. Wash the
screen and bowl
in
paraffin
and
blow
through the screen
with
compressed
air. Clean out the
pump
chamber
if
necessary, and
renew the bowl
gasket.
ReÍit the
screen and
bowl
and
tighten the
holding
screw
Íirmly
by
hand.
Check
that the
pipe
hose is Íully
engaged with the
pump pipe.
P404
2:7
Slow-running
adjustment, routine
maintenance
2:8 Dismantling and
inspection
oÍ carburetter
2:9
Reassembling
the carburetter
2:10
Carburetter,
Zenith
34
WIM
2 :11 Fault diagnosis
2:3 Removing
and
dismantling the
fuel
pump
Detach
the main Íuel
pipe
hose
from
the
pump
and
plug
the hose to
prevent
fuel loss. Disconnect the
carburetter
Íeed
pipe
from the
pump.
Remove
the
attaching nuts and
remove the fuel
pump
and
gasket.
Remove the bowl,
gasket
and
filter screen
as
detailed
in
Section
2:2. Mark across
the Ílanges of the
pump
cover and body
to ensure correct
relationship when
reassembling. Remove the
pump
cover.
Release
the
diaphragm
assembly by depressing and
turning
it through 90 deg. Carefully
prise
out
the valves
and
remove the
gaskets.
Do
not
remove the Íocker arm
unless excessive
wear
of
the arm
and
associated com-
ponents
is evident.
Inspect the rocker arm and components
for wear. To
renew, remove the
rocker
arm
pin
retainers, tap out the
pin
and
remove the component
parts.
Install the new
rocker arm, the
link with
a
spacing washer on each side,
and the arm
spring. Fit the
pin
and secure
it with new
retai ners.
To
renew the
diaphragm
rod
oil seal,
scrape
away
the
staked
metal securing the seal
retainer and the body
boss.
Withdraw the
retainer
and
the seal. Install two new oil
seal
washers and a new
retainer if the original
was
damaged
during removal. Stake
the body boss at four
points
to secure the
retainer.
23
To Next Page
Loading...
Need help?
General
