MG Midget Mark II User Manual

CARBURETTER ADJU
Slow-running adjustment and synchronization
When the engine is fully run in the slow running may require adjust: en t.' his
must only be carried out when the engine has reached its normal runnin '
t m-
perature.
As the needle size is determined during engine development, tuning of the
carburetters is confined to correct idling setting. lacken the actuating arms on
the throttle spindle interconnection.
Close b th throttles fully by unscrewing
the throttle adjusting screws, then open each throttle by screwing down each
idling adjustment screw one turn.
Remove the pistons and suction
chambers, and disconnect the choke control
cable. Screw the jet adjusting nuts until each jet i flush with the bridge
of its
carburetter, or as near to this as possible (both j ts being in the same relative
position to the bridge of their respective carburcttcr ). Replace the pistons
and
suction chamber assemblies, and check that the pi tons fall freely onto the
bridge of the carburetters (by means of the piston lifting pins). Turn down each
jet adjusting
nut two complete turns (12 flats).
The Type HS2 carburetter,
showing:
I. Throttle adjusting screw.
2. Butterfly operating fork.
3. Fast-idle adjusting screw.
4. Jet link securing screw.
5. Jet locking nut.
6. Flat-chamber securing nut .
7. Jet adjusting nut.
Restart the engine, and turn the throttle adjusting screws to give the desired
idling speed by moving each screw an equal amount. By listening to the hiss in
the intakes, adjust the throttle adjusting screws unt il the intensity of the hiss is
similar on
both intakes. This will synchronize the throttles.
When this is satisfactory, the mixture should be adjusted by screwing each
jet adjusting
nut up or down by the same amount until the fastest idling speed
is obtained consistent with even firing. During this adjustment it is necessary
to press the jets upwards and ensure
that they are in contact with the adjusting
nuts.
As the mixture is adjusted the engine will probably
run faster and it may
therefore be necessary to unscrew the throttle adjusting screws a little, each by
the same amount, to reduce the speed.
Now check the mixture strength by lifting the piston of the front carburetter
~¥ ~pprQ~im~t~!¥ -h i!1 ~ (· 7 ~ mm ~) wh~n;
(1) If the engine speed increases, the mixture strength of the front carburetter
is too rich.
35

MG Midget Mark II Specifications

General

Brand	MG
Model	Midget Mark II
Category	Automobile
Language	English