MG MGB TOURER GHN5 Handbook page 31

Mixture contro
(choke)
Always use the minimum setting for the shortest possible time.
As soon as possible after the engine has started, push the control completely
home.
To obtain a fast engine idling speed, set the control to within the first
+
in.
(12 mm.) approx. of its initial movement.
The control may be locked in the required position by turning the knob a quarter
of a turn clockwise.
Ignition
warning light
Oil pressure
gauge
Warming up
Temperature
gauge
Running in
The light should glow when the ignition is switched on, and go out and stay out
at all times while the engine is running above normal idling speed. Failure to do
so indicates
a
fault in the battery charging system. Check that the fan belt is
correctly tensioned before consulting your Distributor or Dealer.
The gauge should register a pressure as soon as the engine is started up. The
pressure may rise above 80 lb./sq. in. (5.6 kg./an2) when the engine is started
from cold and as the oil is circulated and warmed the pressure should then drop
to between 50 and 80 lb./sq. in. (33 to 5.6 k g . / ~ m . ~ ) at normal running speeds
and to approximately 10 to 25 Ib./sq. in. (.7 to 1.7 kg./cm.=) at idling speed.
Should the gauge fail to register any pressure, stop the engine immediately and
investigate the cause. Start by checking the oil level.
Research has proved that the practice of warming up an engine by allowing it to
idle slowly is definitely harmful. The correct procedure is to let the engine run
fairly fast, approximately 1,000 r.p.m., so that it attains its correct working
temperature as quickly as possible. Allowing the engine to work slowly in a cold
state leads to excessive cylinder wear, and far less damage is done by driving the
car straight onto the road from cold than by letting the engine idle slowly in
the garage.
For automatic transmission see page 32.
Normal operating temperature is reached when the pointer is in the 'N' sector.
Overheating may cause serious damage. Investigate immediately any upward
change in the temperature gauge reading. Check coolant level and fan belt tension.
The treatment given to a new car will have an important bearing on its subsequent
life, and engine speeds during this early period must be limited. The following
instructions should be strictly adhered to.
During the first 500 miles (800 km.):
DO NOT exceed 45 m.p,h. (72 km.p.h.).
DO NOT operate at full throttle in any gear.
DO NOT allow the engine to labour in any gear.