Carburetor Description; Carburetor Structure And Operation - Datsun 620 Series 1977 Service Manual

Engine Fuel
CARBURETOR
CONTENTS
DESCRIPTION
EF 14 CHOKE UNLOADER
EF 23
STRUCTURE
AND
OPERATION
EF 14 ELECTRIC AUTOMATIC CHOKE
EF 24
PRIMARY SYSTEM
EF 15 INTERLOCK OPENING OF PRIMARY AND
SECONDARY SYSTEM
EF 16 SECONDARY THROTTLE VALVE
EF 24
ANTI DIESELING SYSTEM
EF 17
DASH POT
EF 25
FLOAT
SYSTEM
EF 18
ACCELERATING PUMP
EF 25
BOOST CONTROLLED DECELERATION
ANTI DIESELING SOLENOID VALVE
EF 25
DEVICE B C D D EF 1B B C D D CIRCUIT
WITH
FUNCTION
ELECTRIC AUTOMATIC
CHOKE
EF 20 TEST
CONNECTOR
EF 25
DASH POT SYSTEM
EF 20
ALTITUDE COMPENSATOR
ALTITUDE
COMPENSATOR
California modelsl EF 29
California models
EF 20
MAJOR SERVICE OPERATION
EF 29
ADJUSTMENT
AND INSPECTION
EF 21
REMOVAL
EF 29
CARBURETOR
IDLE RPM AND
DISASSEMBLY
AND ASSEMBLY EF
30
MIXTURE RATIO
EF 21
CLEANING AND INSPECTION
EF
34
FUEL LEVEL
EF 22
SERVICE DATA AND SPECIFICATIONS EF 35
FAST
IDLE
EF 22
TROU8LE
DIAGNOSES
AND
VACUUM BREAK
EF 23
CORRECTIONS
EF
36
DESCRIPTION
The carburetors
are
of
down draft
two
barrel
types
which produce
the
optimum
air
fuel
mixture under all
operating
conditions
They
present
several distinct
features of
importance to
the vehicle
owners
A
summary
of
the
features
is
as
follows
1 A
slow
economizer
to
make
a
smooth connection
with acceleration
or
deceleration
during light
load
run
ning
It also
assures
stable low
speed
performance
2
An idle limiter
to
reduce harmful
exhaust
emissions
to a minimum
3 A BC D D
device for
reducing
hydrocarbon
H C emissions
4
An electric
automatic
choke
to
facilitate
cold
starting and
to
reduce
exhaust
emissions
5
An anti
dieseling
solenoid
to
eliminate
dieseling
run on
6
A
power
valve
or vacuum
actu
ated booster to ensure
smooth
high
speed operation
7
The
carburetor
comes
equipped
with dash pot which
ensures smooth
deceleration
without
engine stall
under all
operating
conditions
8
The hand operated altitude
com
pensator
is
installed
in
the California
models
EF 14
STRUCTURE
AND
OPERATION
These
carburetors
consist
of
a
primary system
for
normal running
and
a
secondary
system for full load
running
A
float system
common
to
both
primary and
secondary
systems a se
condary
switch
over
mechanism
an
accelerating
mechanism
etc
are
also
attached
An anti
dieseling
solenoid
valve and
a power
valve mechanism
are
also
installed
The hand
operated
altitude
com
pensator
corrects air fuel
mixture
to
an
optimum
ratio