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highest speed
Re
adjust
the throttle stop
screw
to
reduce the
engine speed
Repeat
thiS
adjustment
until
an
engine
speed
of 550 rpm
has
been
obtained
Care
should be taken
not to
screw
In
the
slow running volume control
screw to
tightly
as
otherwise the
tip
of the
screw
might
be
damaged
Dashpot adjustment
ThiS
adjustment
IS
only
necessary
on
the Datsum 1600 fitted
With
automatic
transmission
With the
engine
at
operating
temperature
check that the throttle lever Will touch the
dashpot
stem
when the
engine
IS
running With 1800
2000
rpm
There
should be
no
load
on
the engine
Fig
E
161
If thiS
IS not
the
case
slacken the dash pot locknuts and
turn
the dash pot
to
the
nght
or
left until the throttle lever touches the dash
pot
stem at
the
specified
engine
speed
In thiS condition
the clearance
between the throttle valve and the throttle chamber wall should
be 08
mm
0071
In
I
corresponding
to
a
throttle valve
angle
of
lO
SU TYPE TWIN CARBURETTORS
Dismantling
Unscrew the
plug
and Withdraw the piston
damper
Take
out
the
two suction
chamber secunng
screws
11ft off the suction
chamber and Withdraw the piston and Jet needle
Disconnect
the rod from the bottom of the Jet
and the
nylon
feed tube
from the base of the float chamber
Unscrew the
Jet
adjusting
nut
and the spnng Unscrew the Jet
beanng locking
nut
Remove the float chamber
cover
secunng bolts and Withdraw
the float
Screw
out
the needle valve
assembly
The
dismantling
stages
are
shown
In
Figs
E 24 E 25 and E 26
CARBURETTOR
InspectIon
Note the condition of the needle valve and the
seating
Fit
a
new
needle valve and
seating
If necessary
If the Jet needle
IS
bent
or
otherwise
damaged
Withdraw the
locking
screw In
the
piston and
fit
a
new
needle
Push the needle
In
until the
shoulder
IS
flush With the lower face of the
piston
Fig
A
271
Clean and
dry
the piston
assembly
Lubncate the piston rod
WIth thin 011
CARBURETTOR
Assembly
Reverse the
dlamantllng procedure
and
centre
the Jet
Centnng
the
Jet
Screw the Jet
adjusting
nut
up
as
far
as
poSSible
11ft the piston
With the
lifting
pin and allow
It to
drop
It should
drop freely
onto
the
bndge
With
a
soft metallic click
Repeat
wltn
the
adjusting
nut
screwed
fully
down
If the piston does
not
fall
freely
In
either
of
the
tests
proceed
as
follows
Disconnect the rod from the bottom of the
Jet
and the feed
tube from the base of the float chamber Pull
out
the Jet and
the tube
Unscrew and
remove
the
Jet
adjusting
nut
and the
spnng
Refit the
adjusting
nut Without the spnng and
screw It
up
as
far
as
pOSSible
Slacken the
Jet
bearing
lock
nut
until the
beanng
can
be turned
With the
fingers
Remove the
piston
damper
and press the
piston
down
onto
the
bndge Tighten
the
lock nut
tift lhe pjS
on
and nQ 1l
whetlliij
IS
falls
freely
fully
1 9w
ir
the
30
adjusting
nut
and
check
again If the second check
produces
a
sharper
click than the first repeat the
centnng
Refit the
parts
that
have
been removed
pour thin 011
Into
the hollow rod of
the piston
damper
to
Within 0 5
In
12 7
mml
of the
top
of the
rod
CARBURETTOR
Adjustments
The proper
adjustment
of the two carburettors
IS
extremely
Important
In
obtaining peak
vehicle
performance
and
redUCing
fuel
consumption
Carburettor
synchromzsnon
and
idhng adjustment
Remove
the
air
cleaner when
the
engine
has reached
ItS
operating temperature
and slacken the throttle
adjusting
screws
The heads of the
adjusting
screws
must not contact
the throttle
lever
Also make
sure
that the front and
rear
throttle shafts
are
not
connected
Tighten
the
Idling adjusting
nuts
of the front
and
rear
carburettor
by
one
turn
towards the top
of the
carburettors and
gradually
back them off After the
nuts
have
been turned
approximately
half
a
turn
the
nuts
Will
contact
the
needle heads
Back off the
nuts
from thiS pOSition
by
approx
one
and
a
half
turn
Make
sure
that the
Idling adjusting
nuts
of
both carburettors
are In
the
same
pOSition The dimenSion
A
adjustment
descnbed
later
between the Jet
bndge
and the
needle head should then be approx
1 5
mm
0591
In
I
Screw
In
the throttle
adjustment
screws
of the front and
rear
carburettors and
start
the engine The
engine should
retain Its
operation
temperature
before carrying
out
the
next
step
Now
turn
the throttle
adjusting
screw
of both carburettors
to
reduce the engine
speed
to
approx 600
700 rpm
The engine
should
turn
over
smoothly
and consistent
If
a
flow
meter
IS
available
apply
the
Instrument to
the front carburettor
flange
and
turn
the
adjustment
screw on
the flow
meter
so
that the
upper end
of
the float
In
the
glass
tube
IS In
line With the scale
Llft off the flow
meter
and
re
apply
It to
the
rear
carburettor
Without
altering
the
setting
of the flow
meter
adjusting
screw
If
the
pOSItion
of the float
IS
not
In
line With the scale
adjUst
the
rear
carburettor throttle
adjusting
screw
to
align
the float With
the mark
on
the scale
With the carburettor flow
correctly adjusted tighten
the
Idling
adjusting
nuts
of both carburettors
by
approx
1 8 of
a
turn
and
stop
the
adjusting
of the
nuts at
a
pOint
where the engine
speed
IS
fastest
and smoothest Without missing
or
hunting
If thiS
point
cannot
be detenmned
bnng
the
nuts
back
to
their
onglnal
positions and
unscrew
them from thiS
pOSition
until the
engine
runs
fastest und smoothest
Then slacken the throttle
adjusting
screws
of the front and
rear
carburettors and
adjUst
the engine
speed
to the
specified
value
of
650
rpm
for standard engines
or
700 rpm
for models With
011 cooler Make
sure
that the
air
flow of both the carburettors
remains
unchanged
Screw
In
the throttle
adjusting
screws
until
their heads
contact
the throttle
connecting
lever
Connect up
the front and
rear
throttle shaft Without
changing
the
Idling
speed
setting
Move
the throttle
interconnecting
shaft
and accelerate the
engine
a
few times When the engine
IS
settled
once more
In
Its
Idling speed
check that the
speed
IS
unchanged
Re check also
the connection of the
interconnecting shaft
Then
turn
tha
Interconnecting shaft
adjusting
screw to
Increase
the engine
speed
to
800
1000 rpm
Check
y
means
of the
flow
meter
Jf
the
Idling
air
flOW
IS
the
same tor
both
carburettors If necessary
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