MG MGB User Manual

THE
ELECTRICAL SYSTEM
N
This
in
turn
may
be due
to
the dynamo
failing
to
charge
the
battery,
and the
■nal
cause
of the trouble
may
be,
perhaps,
a
loose connection in
some
part
of the charging
circuit.
If, after
carrying
out
an
examination
the
cause
of the
trouble
is
not
found, the
equipment
should-be checked.
CHARGING CIRCUIT
1.
Battery
in
low
state
of charge
a.
This
state
will be
shown by lack
of
power
when
starting,
poor
light
from the lamps, and
the
hydrometer readings
below 1.200. It
may
be
due
to
the dynamo
not
charging
or
giving
low
or
intemiittent
output.
The
ignition
warning
light
will
not
go
out
if
the
dynamo fails
to
charge,
or
will
■icker
on
and
off
in
the
event
of intermittent
output.
b.
Examine the
charging and
■eld
circuit wiring.
Tighten
any
loose connections,
or
renew
any
broken cables.
Pay particular
attention
to
the
battery
connections.
0.
Examine
the
dynamo
driving
belt; take
up
any
undue
slackness by
swinging
the dynamo
outwards
on
its
mounting
after
slackening the
attachment bolts.
Check the regulator
setting,
and adjust
if
necessary.
e.
If,
after
carrying
out
the above,
the trouble
is
still
not
cured, have the
equipment
examined.
2. Battery
overcharged
This will be
indicated by
burnt-out
bulbs,
very
frequent
need for
topping
up
the battery,
and high
hydrometer
readings. Check the
charge
reading with
an
ammeter
when
the
car
is running.
It
should be
of the order
of only
3
to
4
amps.
If the
ammeter
reading
is
in
excess
of this value
it is
advisable
to
check the
regulator
setting,
and adjust
if
necessary.
STARTER MOTOR
1. Starter
motor
lacks
power or
fails
to turn
engine
a.
See if
the
engine
can
be
turned
over
by
hand. If
not,
the
cause
of the
stiffness
in
the
engine
must
be
located
and remedied.
b.
If the
engine
can
be
turned
by
hand ■rst
check that
the trouble
is
not
due
to
a
discharged
battery.
c.
Examine the connections
to
the battery,
starter,
and
starter
switch, making
sure
that they
are
tight and that
the cables
connecting
these
units
are
not
damaged.
d.
It is
also
possible that the
starter
pinion
may
have
jammed
in
mesh with the
■ywheel.
To
disengage the
pinion
rotate
the squared end
of the
starter
shaft by
means
of
a
spanner.
2.
Starter
operates
but does
not
crank the
engine
This fault will
occur
if the
pinion
of the
starter
drive
is
not
allowed
to
move
along
the
screwed sleeve
into
engagement
with the ■ywheel, due
to
dirt
having collected
on
the
screwed
sleeve.
Remove
the
starter
and clean the sleeve
carefully with
paraf■n
(kerosene).
MGB.
Issue4.
25729
3. Starter
pinion
will
not
disengage from ■ywheel
when
engine is running
Stop the
engine
and
see
if the
starter
pinion is
jammed
in
mesh with the ■ywheel, releasing
it
if
necessary
by
rotation
of the
squared end
of the
starter
shaft.
If the
pinion
persists
in
sticking
in
mesh have the
equipment
examined.
Serious
damage
may
result
to
the
starter
if
it
is
driven by
the
■ywheel.
LIGHTING CIRCUITS
l. Lamps give
insufficient
illumination
a.
Test the
state
of
charge
of
the battery,
recharging
it
if
necessary
from
an
independent
electrical supply.
b.
Check the
setting
of the lamps.
c.
If the
bulbs
are
discoloured
as
the result
of long
service
they should be renewed.
2.
Lamps
light
when switched
on
but gradually fade
out
As
paragraph
1
(a).
3.‘
Brilliance
varies
with
speed
of
car
a.
As
paragraph
1
(a).
b. Examine the battery
connections,
making
sure
that
they
are
tight, and
renew any
faulty cables.
Section N.19
BI-METAL RESISTANCE
INSTRUMENTATION
General description
The bi-metal
resistance equipment
for
fuel and
temperature
gauges
consists
of
an
indicator head and
transmitter
unit
connected
to
a
common
voltage
stabilizer. The
system
by
which
the
equipment
functions
is
voltage-sensitive
and
the
voltage
stabilizer
is
necessary
to
ensure
a
constant
supply of
a
predetermined
voltage
to
the
equipment.
wiLaLnlmmlH
9
lm'm
E
1".
@
H»
I x
GB
L...
..
Fig. N.20
The bi—metalresistanceinstrumentation circuit
E]
:1
A956
0A
2.
Control box. 38.
Ignition switch.
3.
Batteries
(12—volt). 46.
Coolant
temperature
gauge.
4.
Starter
solenoid. 47.
Coolant
temperature
19. Fuse (A3—A4).
transmitter.
-
34.
Fuel
gauge.
64.
Voltage stabilizer.
:25.
Fuel tank
unit.
.
N25

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English