1973 DATSUN B110 fuel type

ENGINE

Replacing
fuel
filter

Check
for
a

contamination
element
water
deposit
and

defection

Fig
ET
15
Fuel
strcrineT

All

engines
use
a

cartridge
type
strainer
If
it
is
found

to
be

defective

replace
as
an

assembly

Checking
fuel
lines

hoses

pipings
connections
etc

Check
fuel
lines
for
loose
connections
cracks
and

deterioration

Retighten
loose
connections
if

necessary

replace
any

damaged
or

defective

parts

THROTTLE
OPENER
CONTROL

SYSTEM

The
function
of
the
throttle

opener
is

to

open
the

throttle
valve
of
carburetor

slightly
in

vehicle
decelera

tion

During
deceleration
manifold
vacuum
rises

and
a

quantity
of
mixture
in
the

enigne
is

not
sufficient
so
that

a
normal
combustion
can
not
continue
and
a

great

amount
of
unburned
HC
is

emitted
The
carburetor

equipped
with
the
throttle

opener
supplies
the

engine

with
an

adequate
charge
of
combustible
mixture
to

keep
proper
combustion

during
deceleration

resulting
in
re

markable
reduction
of

He
emission

The

operation
of
the

throttle

opener
is
as
follows
A

schematic

drawing
of
the

system
is
shown
in

Figure

ET
16

At
the

moment
when
the
manifold

vacuum
increases

as

occurs

upon
deceleration
the

control
valve

opens
to

transfer
the
manifold

vacuum
to

the
servo

diaphragm

chamber
and
the
throttle
valve
of
the
carburetor

opens

slightly
As
the
vehicle

speed
decreases

above
16

km
h

10

MPH
for
manual
transmission

only
the
manifold

vacuum
lowers
to
the

predetermined
value
The
vacuum

control
valve

begins
to
close

gradually
keeping
the

manifold

vacuum
at
the

predetermined
constant
value

As
a

result
both
low
HC
emission
and
normal

engine

brake

during
deceleration
are

obtained

The

altitude
corrector
is

provided
with
a

slight
preload

to

compensate
the

variation
of
the

atmospheric
pressure

Vacuum

control
solenoid

The

purpose
of
this
control
is
to
return
the

speed
of

engine
to
the

prescribed
idling
positively
To
be

accurate
the

control

prevents
the
throttle

opener
from

taking
normal

operation
when
vehicle

speed
is
below

16

km
h

IO
MPH
for
manual
transmission

equipped

model
or
when
transmission
is

placed
in

N
or

P

position
for
automatic
transmission

equipped
model

Current
flows

through
the

solenoid
when
vehicle

speed

falls
below
16
km
h
10

MPH
on

manual
transmission

equipped
model
or
when
the
transmission
is

placed
in

N
or

P

position
on
automatic
transmission

equipped
model

As
this
takes

place
the
needle
valve
is
lifted
off
its
seat

directing
air
from
the
air
chamber
to
the
servo

diaphragm
This
releases
the

operation
of
the
throttle

opener

When

vehicle

speed
goes
over
16
km
h

IO
MPH
or

when
transmission

is

placed
in
a

position
other
than

N

or
P

position
the
solenoid
is

deenergized

allowing
the
throttle

opener
to
take
normal
action

to

reduce
He
emission
to
a
minimum

ET
10

ENGINE

Caution

lock
the
front

and
rear
wheels

by
fully

pulling
the

parking
brake
lever
before
con

ducting
this
test

Fig
ET
32

Checking
for
operation
of
vacuum

advance

system

If

any
objection
is

found

by
the
check

mentioned

above

either
of
the

following
defects

may
be
the

cause

Poor
connection
or

broken
harness
and
fuse

2
Air

leakage
resulting
from

poor
connection
of
vacu

um
tube

3
Incorrect

operation
of

Top
switch

4
Defective

operation
of
vacuum

cutting
valve
sole

naid

5
Incorrect

operation
of
thermo
switch

Testing
of

Top
switch

1
Make
sure
of
insulation
between
lead
wire

terminal

of
transmission
switch
and
switch

body

2

Disconnect
lead
wires
at
the
switch

and
connect

ohmmeter
to
tenninals

3
Ohmmeter

should
indicate

infmity
co
when
shift

lever

is
in

Top
gear
position
And
it
should
indicate

zero
at
other

gear
position
including
Neutral

posi

tion

4
If

it
does
not

work

properly
in

step
3

replace
the

switch
with
a
new
one

Testing
of
thermo
switch

I

MaJ
e

sure
of

insulation
between
lead
wire
terminal

of
thermo
switch
and
thetmo
switch

body

2

Disconnect
lead
wire

at
switch
and
connect
ohm

meter
to
terminals
Ohmmeter
should
indicate
zero
when

temperature

indicate
the

passenger
compartment
is
above
l30C

550F

4
If
it
does

not
work

properly
in

step
3

replace

thermo
switch
with
a
new

one

AUTOMATIC

TEMPERATURE

CONTROL
AIR
CLEANER

A
T
C
AIR

CLEANER

Replacing
carburetor
air
cleaner

filter

The

paper
element

viscous

type
has
been

specially

treated
to

eliminate
bother

of

cleaning
until

replacement

It

should
be

replaced
with
a

new
one
at

regular
intervals

or
more
often

according
to
the

operating
conditions

Checking
hot
air
control
valve

Inspection

Among
the

possible
troubles
of
this
device
the

most

liable
is
the

permanent
opening
of
valve

This
trouble
is
not

noticed
in
warm
weather
but
in

cold
weather

appears
as

poor

performance
of

engine

such

as

tardy
acceleration
hesitation
or

engine
stall
In

such

case
first

inspect
this

device
before

checking
the

carburetor

Another
trouble
which

might
be

expected
is
that
the

underhood
air
is

kept
closed

by
the
valve

regardless
of

the

temperature
of
suction
air
around
the

sensor
while

the

engine
is

running
This
ttOuble

appears
in
the

form

of

extremely
excessive
fuel

consumption
or
decrease
in

power

The

inspection
of
this
device

should
be

proceeded
as

follows

Fig
ET

33
Correct

position
of
hoses

ET
20

FUEl
SYSTEM

AUTOMATIC

TEMPERATURE
CONTROL

AIR

CLEANER

A
T

C
AIR
CLEANER

CONTENTS

DESCRIPTION

Air
cleaner

element

Automatic

temperature
control
air
cleaner
EF
1

EF
1

EF
2
TEMPERATURE
SENSOR

Removal

and
installation
EF
4

EF
4

DESCRIPTION

Air
cleaner
element

This
air
cleaner

element
is
of
a
viscous

paper

type
and

does
not

require
any
cleaning

regardless
of
contamination

until
it
is

replaced
with
a
new

one
Note
Never
treat

element

by
brushing
or

air

blasting

before
the
time
for

replacement

Fig
EF
l

Replacing
air
cleaner

EF

1

FUEl
SYSTEM

FUEL
STRAINER

DESCRIPTION

The

fuel
strainer
is
of
a

cartridge
type
It

uses

paper

element
as
strainer
element
which
can
be

checked
for

condition

from
outside
This
strainer
cannot
be
cleaned

Replace
the
strainer
at
the

specified
service
interval
or
if
it

becomes

clogged
or

restricted
REMOVAL

Disconnect
inlet
and
outlet

fuel
lines
from
fuel

strainer
and

remove
fuel
strainer

Note
Before

disconnecting
fuel
lines
use
a
container
to

receive
the

remaining
fuel
in
lines

r

@
I

I

Il
QY
I

I
I
elementl
3
Cover
@

EF005

Fig
EF
10
Sectional
view

of
caTtridge
type
fuel
stTaineT

FUEL
PUMP

CONTENTS

DESCRIPTION

FUEL
PUMP

TESTING

Static

pressure
test

Capacity
test
EF
5

EF
6

EF
6

EF
6

DESCRIPTION

The
fuel

pump
transfers

gasoline
from
the
tank
to
the

carburetor
in
sufficient

quantity
to
meet

engine
require

ments
at

any

speed
or
load

The
fuel

pump
is
of
the

diaphragm
type
REMOVAL
AND
DISASSEMBLY

INSPECTION

ASSEMBLY
EF
7

EF
B

EF
B

The
fuel

pump
consists
of
a

body
rocker

arm
and
link

assembly
fuel

diaphragm
fuel

diaphragm

spring
seal

inlet
and
outlet
valves

The
fuel

diaphragm
consists
of

specially
treated
rubber

which
is

not
affected

by
gasoline
held

together
with
two

metal
discs

and
a

pull
rod

EF
5

ENGINE

INSPECTION

Check

the

upper
and
lower
bodies
for
cracks

2

Check
the
valve

assembly
for

wear
of
the
valve
and

valve

spring
Blow
the
valve

assembly
by
breath
to

examine
its

function

3

Check
the

diaphragm
for
small
holes
cracks

and

wear

4

Check
the
rocker

arm
for
wear
at
the

portion
in

contact
with

the
camshaft

5

Check
the
rocker
arm

pin
for
wear
since
a
worn

pin

may
cause
oil

leakage

6

Check
all
other

components
for

any
abnormalities

and

replace
with
new

parts
as

required
ASSEMBLY

Assembly
is
done
in
reverse
order
of

disassembly
For

reassembly
and

reinstallation
the

following
matters

should
be
noted

Use
new

gasket

2
Lubricate
the
rocker
arm

link
rocker
arm

pin
and

lever

pin
before
installation

3
To

test
the
function

position
the

fuel

pump
assem

bly
about
I

meter
3
3
ft
above
fuel
level
with
a

pipe

connecting
the
fuel

pump
and
the
fuel

strainer
and

operate
the
rocker

afm

by
hand
If
fuel
is
drawn

up
soon

after
the
rocker
arm
is
released

the
function
of
the

pump

is

satisfactory

CARBURETOR

CONTENTS

DESCRIPTION

STRUCTURE
AND
OPERATION
EF

8

EF

9

EF
10

EF
11

EF
12

EF
12

EF
12

EF
14

EF
14

EF
15

EF
15

EF
16

EF

16
Primary
system

Secondary
system

Anti

dieseling
solenoid
valve

Float

system

Electric
automatic
choke

ADJUSTMENT

Idling
adjustment

Fuel
level

adjustment

Fast
idle

adjustment

Vacuum
break

adjustment

Choke
un
loader

adjustment

DESCRIPTION

The
carburetors
are

of
a

downdraft

type
which
is

designed
and
built

to
increase

power
and

fuel

economy
as
Bi
metal

setting

Adjustment
of

interlock

opening
of

primary
and

secondary
throttle
valves

Dash

pot
adjustment

MAJOR
SERVICE
OPERATIONS

Removal

Disassembly

Cleaning
and

inspection

Assembly
and
installation

JETS

SERVICE
DATA
AND
SPECIFICATIONS

TROUBLE
DIAGNOSES
AND

CORRECTIONS
EF
17

EF
18

EF
18

EF
19

EF
19

EF
19

EF
21

EF
22

EF
22

EF
22

EF
22

well
as
to
reduce
the

emission
of
exhaust

gases

These
carburetors

present
several
distinct
features
of

importance
to
the

car
owners

A

summary
of
features
is
as
follows

EF
8

FUEl
SYSTEM

Secondary
throttle
valve

is

operated
by
throttle
lever

The

high

power
and

good
acceleration
are

gained
with

combination
of

the

auxiliary
valve

2

Accelerating
pump
gives
excellent

acceleration

3

The

power
valve
mechanism
is
of
a

vacuum
actuated

boost

type
and

improves

high
speed
driving

4
The

throttle

opener
control

system
Refer
to
Section

ET

incorporates
a

servo

diaphragm
The
servo
dia

phragm
helps
open
the
throttle

valve
at
a

decreasing
speed

so
as

to
reduce

the
emission
of

hydrocarbons
to
a

minimum

5
An

anti
dieseling
solenoid

is
used
as
a

means
of

preventing
dieseling
When
the

ignition
key
is
turned
off
the
fuel

passage
involved
in
the
slow

system
is

closed

and
the
fuel

supply
is
shut

down

completely

6
In

the
choke

mechanism
an

electric
automatic

choke

is
used
to

automatically
control
the
choke
valve

operation

during
the
warm

up
of
the

engine

7
The
carburetor

for
automatic
transmission
is

equipped
with
so
called

dash

pot
that

is
it
makes
smooth

decelerating
without

engine
stall
at

any

operating
condi

tion

These

carburetors
are

quite
similar
in

appearance
as

explained
above

except
the

dash

pot
for
the
au
tomatic

transmission
model
The

differences
in

performance
are

explained
in
the

following
as

necessary

for
Manual
transmission

for
4utomatic
transmission

Fig
EF
14
External
view

of
carburetor

STRUCTURE
AND
OPERATION

These

carburetors
consist
of

the

primary
system
for

normal

running
and

secondary
system
for
full

load

running
The

float

system
which
is

commonly
used

by
the
primary
and

secondary
systems
the

secondary
switch
over

mechanism

accelerating
mechanism
etc
are

also
at

tached

The
anti

dieseling
solenoid
valve
and
the

power
valve

mechanism

are
used

The

carburetor
is
of
down
draft
two
barrel

type

EF
9

FUEl

SYSTEM

Idling
and
slow

system

Passing
through
the
main

jet
the
fuel

passage
is

separated
from
main

line
fuel
flows

through
the

slow

jet
primary
slow
air
bleed
is

ejected
from
the

by
pass

hole
and
idle

nozzle

Accelerating
mechanism

Cj

f

li

Ip

j

1

2

3

4
5
Inlet
valve

6
Outlet
valve

7
Primary
throttle
valve

8

Pump
connecting
rod
Pump
lever

Pump
nozzle

Piston

Piston
return

spring

Fig
EF
17

Accelerating
mechanism

A

mechanical
accelerating

pump
synchronized
with
the

throttle
valve
is
used

When
the
throttle
valve

is
closed
the

piston
rod
is

pushed
up
with
the

linkage
which

pushes
up
the

piston

through
the

piston
return

spring

When
the

piston
comes
down

the
inlet
valve
closes
the

outlet
valve

opens
and
the

fuel
within
the

pump
is

blown
out
from

the

pump
jet
by
the

compressed
piston

return

spring
The

fuel
hits

against
the
side
wall
of
the

small
venturi

becoming
minute

drops
and

compen

sating
trancient

sparseness
of
the

fuel

Power
valve
mechanism

The

power
valve
mechanism
so

called
vacuum
actuated

boost

type
makes
use
of
the
downward

pulling
force

of
the

air
stream
below
the

throttle
valve

When

the
throttle
valve
is

slightly
opened
during
light

load

running
a

high
vacuum
is
created

This
vacuum

pulls
the
vacuum

piston
upward
against

the

spring
leaving
the

power
valve
closed

When
the

vacuum
is

lowered

during
full

load
or

accelerating
running
the

spring
pushes
the
vacuum

piston
downward

opening
the

power
valve
to
furnish

fuel

EF
11
Secondary
system

Secondary
main

system

When
the

primary
throttle
valve
is
wide

open
and
the

engine
produces
high
power
the

secondary
throttle

valve

begins
to

open
by
the

linkage

However
the

auxiliary
Y
J

lve
does

not

open
at
a
slow

speed
due
to
the

counterweight
connected
to
the
valve

shaft

As
the

engine
picks
up

speeds
the

auxiliary
valve

opens

against
the

load
of
the

counterweight
and
the
second

ary
system
starts

operation
for

high
power
operation

The
fuel

flowing
out
of
the

passage
at
the
bottom
of

the
float

chamber

passes
through
the

secondary
main

jet
The
fuel
is
mixed

with
the
air

coming
from
the

main
air

bleed
and
the
mixture
is
blown
into
the

venturi

through
the
main
nozzle

When
the

primary
throttle
valve
is
in
the
full

open

position
the

secondary
throttle
valve
is
also

fully

opened

t

2

3

4
5

Auxiliary
valve

6
Secondary
throttle
valve

7

Primary
throttle
valve

8

Primary
main

jet
Counter
lever

Primary
main
nozzle

Primary
main
air
bleed

Counterweight

Fig
EF
1B
At

full
open
slow

speed

j

1

2

3

4

5

6
Counter

weight
7

Secondary
main
air
bleed
8

Secondary
main
nozzle
9

Counter
lever
10

Primary
main
nozzle
11

Primary
main
air

bleed
Secondary
main
jet

Auxiliary
valve

Secondary
throttle
valve

Primary
throttle
valve

Primary
main

jet

Fig
EF
19
At

full
open
high
speed

FUEL
SYSTEM

5
Check
venturi
clusters

for
loose
or
worn

parts
If

damage
or
looseness
exists

replace
cluster

assembly

6
Check
the

linkage
for

operating
condition

7

Inspect
the

operation
of

accelerating
pump

Pour

gasoline
into
the
float
chamber
and

operate
the

throttle
lever

Check
condition
of

gasoline
injection
from

the

accelerating
nozzle

Assembly
and
instalIetion

Assemble

and
install
the
carburetor
in

reverse

sequence

of

disassembly
and
removal

Replace
the

gaskets
if

necessary

When

disassembling
and

reassembling
the
interlock

link

and

related

components
be
careful
not

to
bend
or

deform

SPECIFICATIONS
AND
SERVICE
DATA

Carburetor
model

Applied
engine

Type

Outlet
diameter
mm
in

rom

in
Venturi
diameter

Main

jet

Main
air
bleed

Slow

jet

Slow
air
bleed

Power

jet

Float
level
H
rom

in

Interlock

opening
of

primary
and

secondary
throttle
valve
G
I

Throttle
valve

opening
480
mm
in

Auto
choke

Fast
idle

setting
clearance
A

mm

in

Manual
transmission

Automatic
transmission

Vacuum
break

gap
between

choke
valve
and

carburetor

body
8

mm
in

Manual
transmission

Automatic
transmission

EF
21
the

components

Reassembly
carefully
and

correctly
so
that

all
interlock

links

operate
smoothly

JETS

The
carburetor

performance
depends
on
jets
and
air

bleeds
and
the
vehicle
emissions

largely
depends
on

the

carburetor

performance
That
is

why
these

components

are
manufactured
with
utmost
care

To
clean
them

use

gasoline
and
blow
air
on
them

Changing
jet
or
air

bleed
size

may
cause
ill

vehicle

emission

So

they
should
not
be

changed
their

numbers

DCH3064
for

Manual
transmission

DCH306
5

for
Automatic
transmission

Downdraft

Primary
Secondary

26
1
024
30
1
181

20
0
787
26
1
024

1
95

1
140

1
80

1
80

1
43

1
50

1
215

1
100

1
60

18
to
20
0

709
to
0
748

5
8
0
2283

0

80
to

0
88
0
0315
to
0

0346

1
07
to
1
17
0
0421
to
0

0461

1
140
to
1
260
0
0449

to
0
0496

1

205
to
1

335
0

0474
to
0
0526