Datsun 1200 - CARBURETTOR

1 Ct
RBIJRETTOR
Fuel
System
2
The Hitachi
DCG286
and
DCG306
carbureltors are
filted to the Datsun 1000 and
1200
engines respectively
and
are almost identical in construction
The
major
difference
between the
two carbur ettors
is
the
power
valve mechanism which was
introduced
to
the
1200 version to
improve high speed driving
As
both
carburettors
are
quite
similar overhaul
procedure
etc
as
outlined
in the
carhurettor
section will be
applicable
to both models unless otherwise stated
The carburettor is of the twin barrel
type
with each
barrel
incorporating
a
multiple
venturi
system
The barrels
provide
a
primary
and seco
ndary system
and
each barrel
shares a
common
air horn and
separate
main nozzle
and throttle
valve
The
primary system provides
suitable mixtures for low
speed
moderate
speed
and
acceleration
It also
provides
adequate
mixtures for
starting
when the choke
plate
is
closed
The
secondary
bore
provides
mixtures for
high speed
and
also for
full throttle
openings
at low
speed
A
high
speed
valve
which is
incorporated
in
the
secondary system opens against
a
counterweighted
lever to
enable the
secondary system
to maintain
full
mixture for
high power operation
TO REMOVE AND
INSTAL
I
Raise the
engine
bonnet and
fit fender covers to
both front fenders
2 Remove the air cleaner
assembly
3 Disconnect
the fuel
feed
pipe
4 Disconnect
the
distributor
vacuum advance
pipe
5 Disconnect the
choke control
cable
6
Detach
the tluottle
cable from
the
carburettor
throttle lever
PRIMARY THROTTLE VALVE
T
d
SPRING
lir
THROTTLE
SCREW
E SCREW
HIGH SPEED VALVE
Carnurettor
Flange
and Main
Body
with Main Jets Throttle
and Idle Screws
Removed
Typical
of Both Models
7 Remove
the
four
nuts and
washer
ecuring
the
carburettor to the
inlet
manifold
and
withdraw the
carburettor
and
gasket
from the
engine
Discard
the
gasket
Installation
is a reversal of the
removal
procedure
with
attention
given
to the
full
owing
Use a new
gasket
between the
carburettor and
irilet
manifold If
necessary scrape
the
gasket
surfaces
clean
making
sure
that no
foreign
matter is
dropped
into the
inlet
manifold
orifice
NOTE
It
is
good practice
to cover
the inlet
manifold
with
rag
when the carburetfor
is removed
for
overhaul Extensive
engine
damage
mav result
if objects
are
accidentally
dropped
into the induction
Orifice
Ensure that the choke valve is
fully open
when
the
choke control
knob
is in
the full
off
position
at the dash
paneL
Check the
carburettor for
fuel and
vacuum leaks and
adjust
the
idling
speed
to the
specified rpm
after
warm
up
TO SERVICE
When
overhauling
the carburettor
several
items of
importance
should be
observed
to ensure
a
thorough
job
i
All
parts
should be
carefully
cleaned in a suitable
solvent and
then
inspected
for
damage
or
wear
2 Use air
pressure
9nly
to
clear
the various
oritlces
and
channels
3
Replace
faulty
parts
with new ones
When
checking
parts
removed
from the carburettor it is
at
times
v
ry
difficult to be
sure
whether
they
are
satisfactory
for further
service
It
is therefore recommended
that in such
cases
new
parts
be
installed
4
Always
use a new
gasket
kit
when
overhauling
the
carburettor
5 It is
most
important
that
the correct
fitting
35
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