MG MGB User Manual

THE
FUEL
SYSTEM
D
Removing
29.
Remove
the
air
cleaners
as
detailed
in
Section D.5.
30.
Disconnect
the
throttle
cable
from
the
31.
32.
33.
34.
35.
36.
37..
38.
interconnection
lever.
Disconnect
the choke cable.
Disconnect
the breather
pipes
from the carburetter
adaptors.
Disconnect the
fuel feed
hose
from the ■oat
chamber
adaptor.
Disconnect
the
vent
hoses from the
carburetter
adaptor.
Disconnect
the distributor
vacuum
hose from the
carburetter adaptor.
Disconnect
the
return
springs
from the heat shield.
Remove the four
nuts
securing
the carburetters
to
the
inlet
manifold
studs.
Lift
the
carburetter assembly
off.the
inlet manifold
studs.
Dismantling
39.
4o.
41.
42.
43.
44.
45.
46.
47.
48.
49.
so.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
MGB.
Thoroughly
clean
the
outside
of the
carburetter.
Remove
the
piston
damper
and
its
washer.
Mark the
suction
chamber
to
ensure
it
is
re■tted
to
the
same
body.
Unscrew the
suction
piston
chamber
retaining
screws
and
remove
the
identity
tag.
Lift
the
suction
chamber
vertically from the body
without tilting the chamber.
Remove
the
piston spring,
lift
out
the
piston
assembly
and
empty
the oil from the
piston
rod
Unscrew
the needle guide locking
screw.
Withdraw
the needle, guide
and
spring.
Mark the bottom
cover-plate and
body
to
ensure
correct
reassembly,
unscrew
the
retaining
screws
and
remove
the
cover
complete
with sealing
ring.
Remove
the
jet
adjusting
screw
complete with ‘O’
ring.
Remove
the
jet
adjusting lever
retaining
screw
and
spring.
Withdraw the
jet
complete with adjusting
lever,
and
disengage the lever.
Remove
the ■oat
pivot
spindle and ■bre washer.
Withdraw the ■oat.
Remove
the needle valve and
unscrew
the valve
seat.
Unscrew
the
jet
bearing locking
nut
and withdraw
the
bearing complete with ■bre
washer.
Note
the location of the ends
of
the fast idle
cam
lever
return
spring.
Unlock and
remove
the
cam
lever
retaining
nut
and
locking washer.
With the
return
spring
held towards the carburetter
body,
prise
off
the
cam
lever and
remove
the
return
spring.
Unscrew
the
starter
unit retaining
screws
and
remove
the
cover-plate.
Withdraw the
starter
unit
assembly
and
remove
its
gasket.
Withdraw the valve spindle and
remove
the ‘0’
ring,
seals and dust
cap.
Note the
location
and loading of the
ends
of the
Issue
1. 86842
62.
63.
64.
65.
*v
throttle
lever
return
spring
and
remove
the
spring.
Unlock and
remove
the
nut
and tab washer
retaining.
the throttle
levers.
Remove the throttle
lever and throttle
actuating
lever.
Remove
the
throttle disc
retaining
screws.
Close the throttle
and
mark
the
position
of
the
throttle
disc
in
relation
to
the carburetter ■ange.
Do
not
mark the disc
in
the
vicinity
of the
over-run
valve.
Open
the throttle
and carefully withdraw
the disc
from
the throttle
spindle taking
care
not to
damage
the
over-run
valve.
Withdraw the throttle
spindle
and
remove
its
seals,
noting
the
way
it is
■tted
in
relation
to
the
carburetter
body.
Inspection
66.
67.
68.
69.
70.
71.
72.
h
MNr—A
.
Piston.
5.
.
Suction
chamber.
6.
.
Plugs
in piston transfer
Examine the throttle
spindle and
its
bearings
in
the
carburetter body; check for
excessive
play,
and
renew
parts
as necessary.
Examine
the ■oat
needle and
seating
for
damage and
excessive
wear;
renew
if
necessary.
Examine all rubber
seals and ‘0’
rings
for damage and
deterioration;
renew
as necessary.
The cover-plate
sealing
ring
must
be renewed.
Check
condition of
all
■bre
washers
and gaskets;
renew
as necessary.
Clean
the inside of the
suction
chamber
and
piston
rod
guide with fuel
or
denatured
alcohol
(methylated
spirit)
and
wipe
dry.
Abrasives
must not
be used.
Examine
the carburetter body for
cracks
and
damage
and for
security
of the
brass
connections
and the
piston
key.
Examine
the
suction
chamber
and
piston
for damage
and
signs
of
scoring.
3
—I
ill
l
NC
2046
Fig. D.15
Suction
chamber
timing
check
(S.U.
H11“)
Damper.
Time for
suction
chamber
to
fall full
extent
of
piston
holes.
—
4
to
6
seconds.
.
Nut
and
bolt
with large
washer
overlapping
suction
chamber bore.
D.l7

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English