Fu
el system Section P
enable
it
to conform
to
Emission Regulations is
the pre-set
vo
lume control screw (1)
(Fig
ur
e 4).
It must
be
emphasized that this pre-set
adjustment, made at the factory, is
essential for
efficient working
of
the emission control.
Should
it
be
necessary to alter
or
even check
this setting
it
must be carried
out
with
specialised emission control equipment.
Slow
running adjustment can only
be
adjusted
by means
of
the throttle screw (2) (Fi
gu
re 4).
Fig
ur
e 4 Adjusting
slow
running
1 Throttle adjus
tm
ent screw
2
Volume control screw
Diffic
ult
starting with the engine cold
Make sure there is petrol in the float chamber.
fo
r sediment
or
gum can cause the needle
va
lve
to stick in the closed position, thus preventing
the entry
of
fresh fuel when attempting to start.
This can
explain
difficult
starting,
as
fuel in the
float chamber may have evaporated after the
vehicle
has
been standing
for
several hours.
If a sticking needle is suspected, remove the
upper
body
of
the carburettor, and operate the
needle
with
a finger.
Any
tendency
for
the
valve
to
remain closed can usually be overcome
by rinsing it in
methylated spirit. This
will
dissolve gum deposit and wash
off
sediment.
En
sure that the strangler flap in the air intake,
closes completely when the dashboard control
is operated. A bent spindle could cause the
strangler to remain partially or
fully
open and
wou
ld explain inability to start. Check that
thr
ott
le screw is correctly adjusted.
Diffic
ult
starting w ith the engine
ho
t
First check that the needle valve is
of
the correct
6
size.
Having cleaned the assembly, replace
it
with
the correct washer and ensure
it
is screwed
tightly in position.
Examine the
float for damage, and
see
that
it
moves freely on the pivot pin.
If
petrol floods
into the manifold after switching
off
the engine,
it may be a
result
of
excessive pressure from the
fuel pump.
An
addit
ional washer under the needle valve
may
be
effective in preventing flooding, and
could be tried before resorting
to
the fitting
of
a new pump
or
replacing worn parts.
Generally the engine can
be
started by gently
opening the throttle to the
fully
or
near-
fully
open position, then rotating the engine by the
starter
to
cl
ear
the over rich condition.
Excessive fuel consump
ti
on
Having checked to ensure the carburettor has
the standard setting
of
jets and air bleeds fitted,
make certain that
all holes and passages in the
instrument
are
clear. See that the strangler flap
in the air intake opens completely
when
the
choke
control is pushed in.
Dismantle the .economy device to make sure
the diaphragm
material is intact and in
good
condition, also that the gasket is in position
and sound.
If
a replacement diaphragm is needed
it
is always best to
fit
a
new
spring. Carry
out
similar clheck
of
pump diaphragm and
when
assembling
see
that the diaphragm
is
fitted
with
the plain spigot towards the outside.
Cl
ea
n the needle valve, ensure it is fitted
with
the correct washer and screwed tightly in
position. Make sure the
float chamber gasket is
in good condition. Ensure the
float moves freely
on the
pivot
pin.
A n
ew
needle valve,
with
a new washer,
should be fitted
if
the needle shows signs
of
appreciable wear. (Approximately 15,
000
mil
es.
24,000km.) Should
it
be
found after the above
attention, the obvious richness persists, the
explanation may
be
excessive fuel pump pressure
in
which
case
a new pump must be fitted
or
worn
parts replaced.
A loose float chamber plug
or
damaged
alumini
um
washer beneath this
will
cause
leakage,
with
consequent heavier consumption.
Po
or accelera
ti
on
Check that the accelerator pump diaphragm is
sound.
Remove the pump jet to ensure
it
is perfectly
cl
ea
r to give an unbroken stream
of
petrol from
the orifice when the pump is operated, and that
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