1973 DATSUN B110 check engine

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

ENGINE

Step
system

The
construction
of
this

system
corresponds
to

the

idling
and
slow
system
of
the

primary
system

This

system
aims
at
the

power

filling
up
of
the

gap

when
fuel

supply
is

transferred
from
the

primary

system
to
the

secondary

system
The

step
port
is

located

near
the

auxiliary
valve
in
its

fully
closed

state

Anti

uesetmg

solenoid

Ignition
switch

OFF
ON

I

L
i1

7

I
Anti

dieseling
solenoid

valve

When
the

ignition
key
is
turn

to
OFF

current
will

not
flow

through
the

solenoid
and
the
slow

system
fuel

passage
is

closed
to
shut
down

the

engine
without

dieseling

If
anti

dieseling
solenoid
is
found

defective

replace
the

solenoid
as
an

assembled
llnit

Fuse

Ignition
switch

T
Baitery

717

Fig
EF
20
Schematic

drawing
of
anti

dieseling
solenoid

Removal
and

installation
of
anti
dieseling
solenoid

Removal

Solenoid
is

cemented
at

factory
Use

special
tool

STl9
I

50000
to

remove
a

solenoid

When

this
tool
is

not
effective
use
a

pair
of

pliers
to

loosen

body
out
of

position

Installation

I

Before

installing
a
solenoid
it
is
essential

to
clean
all

threaded

parts
of

carburetor
and
solenoid

Supply

screws
in
holes

and
turn
them
in

two
or
three

pitches

2

First
without

disturbing
the

above

setting
coat

all

exposed
threads
with
adhensive
the
Stud
Lock
of

LOCTlTE
or

equivalent

Then

torque
screws
to
35
to
55

kg
cm
30
to
48

in
lb

using
a

special
tool
STl9150000

After

installing
anti

dieseling
solenoid
leave

the

carburetor

move
than
12
hours
without

operation

3
Mter

replacement
is

over
start

engine
and
check
to

be

sure
that
fuel
is
not

leaking
and
that
anti

dieseling
solenoid
is
in

good
condition
Notes
a
Do
not
allow
adhesive

getting
on
valve

Failure
to
follow
this
caution
would
result
in

improper
valve

performance
or

clogged
fuel

passage

b

In

installing
valve
use
caution
not
to
hold

body
directly
Instead

use
special
tool

tight

ening
nuts

as

required

Float

system

Fuel
fed
from
the

fuel

pump
flows

through
the
filter

and
needle
valve
into
the
float
chamber
A
constant
fuel

level
is
maintained

by
the
float
and

needle
valve

As
ventilation
within
the
float

chamber
is
of
an

air
vent

method

Electric
automatic
choke

An
electric
heater

warms
a

bimetal
interconnected
to

the
choke
valve
and
controls
the

position
of
choke
valve

and
throttle
valve
in
accordance
with
the

elapse
of
time

or

the
warm

up
condition
of

engine

The
construction
and
function
of
each

part
of
this

automatic

choke
are

as
follows
See

Figure
EF
21

EF
12

ENGINE

AD
JUSTMENT

Idling
adjustment

Idle

mixture

adjustment
requires
the

use
of
a
CO

meter
When

preparing
to

adjust
idle
mixture
it
is

essential
to
have
the

meter

thoroughly
warmed
and

calibrated

Warm

up
the

engine
sufficiently

2
Continue

engine
operation
for
one
minute
under

idling
speed

3

Adjust
throttle

adjusting
screw
so
that

engine
speed

is
800

rpm
in
N

position
for

automatic
transmission

4
Check

ignition

timing
if

necessary
adjust
it
to

the

specifications

Ignition
timing
50
800

rpm

5

Adjust
idle

adjusting
screw
so
that
ca

percentage
is

1
5
t
0
5

6

Repeat
the

adjustments
as

described
in

steps
3

and

5

above
so
that
ca

percentage
is
1
5

to
5
at
800

rpm

Cautions
a
On
automatic
transmission

equipped

model
check
must
be
done
in
the
0

position
Be
sure
to

apply
parking
brake
and

to
lock
both
front
and

rear
wheels
with
wheel

chocks

b
Hold
brake

pedal
while

stepping
down

on

accelerator

pedal
Otherwise
car
will
rush
out

dangerously

7
On
automatic
transmission

equipped
model
make

sure
that
the

adjustment
has
been
made

with
the
selector

lever
in
N

position

And
then
check
the

specifications
with

the
lever
in

D

position
Insure
that
CO

percent
and
idle

speed
are
as

follows

Idle

rpm
650

ca

percentage

with

lever
in
D

position
15
to
5

If

necessary
adjust
by

progressively
turning
throttle

adjusting
screw
and
idle

adjusting
screw
until
correct

adjustments
are

made

Notes
a
Do
not

attempt
to
screw
down
the
id
Ie

adjusting
screw

completely
to
avoid

damage
to
the

EF
14
tip
which
will
tend
to
cause
malfunctions

b
After
idle

adjustment
has
been
made
shift
the

lever
to
N
or
p

position
for
automatic

transmission

c

Remove
wheel
chocks
before

starting
the
car

Throttle

adjusting

screw

2
Idle

adjust

ing
crew

3
Idle
limiter

cap

4

Stopp
r

Fig
EF
23
Throttle

adjusting
screw
and
idle

adjusting

screw

Idle
limiter

cap

Do
not
remove
this

idle
limiter

cap
unless

necessary

If
this
unit
is

removed
it
is

necessary
to

fe

adjust
it
at

the
time

of
installation
To

adjust
proceed
as
follows

1
Make
sure
that
the

percentage
of

CO
contents

satisfies
the

specifications

2

Install
idle
limiter

cap
in

position
making
sure
that

the

adjusting
screw

can
further
turn
3

8
rotation
in
the

Ca
RICH
direction

j
j
Carburetor

stopper

o

u

o

i

r
3
8
rotation

0

0

Idle
limiter

cap

0
0

CO
lean

Fig
EF
24

Setting
idle
limite

cap

CD

r
Fuel
level

adjustment

@

@

It
I
Float

2

Float
seat
FUEL
SYSTEM

2

Adjust
bottom
float

position
so
that

clearance
h

between

the
float
seat
and
the
needle
valve

stem
is
1

3
to

1
7

mm
0
0512

to
0
0669

in
when
the

float
is

fully

raised
Bend
the

float

stopper

properly
as

required

l

lH

H

ld

up

@

h
Fast
idle

adjustment

Remove
the
bi
metal
cover

3

I
Float

stopper

4
Needle
valve
2
Place
the

fast
idle

arm
on
the
second

step
of

the
fast

idle
earn
Then

adjust
the
fast

idle

adjusting
screw
in
such

a

way
that
the
clearance
of

the
throttle
valve

shown

at

A

in
the
illustration
will
be

the

specifications
See

Figure
EF
26

Fig
EF
25

Adjsuting
float
level

Turn

down
the
float

chamber
to
allow
the
float

coming
into

contact
with
the
needle
valve
and

measure

H
shown
in

Figure
EF
25
When
the
H
is

approxi

mately
19
0
mm

0
748
in

top
float

position
is

correct

The

top
float

position
can
be

adjusted
by
bending
float

seat

Upon
completion
of
the

adjustment
check
fuel
level

with
the

atta
led
level

gauge
Clearance
of
throttle

Engine
revolution

valve
A

mm
in

rpm

Manual
0
80
to

0
88

transmission
0
0315
to
0

0346
1
750

to
2
050

Automatic
1
07
to

l
l
7

transmission
0
0421

to
0

0461
2

650

to
2

950

Fast
idle
earn

steps

5
C

0
J
t

E

r

L

E
I
I

Ogc
l

0

0

JO
A

Throttle
chamber

Fig
EF
26

Adjusting
fast
idle

EF
15

FUEl

SYSTEM

MA
JOR
SERVICE
OPERATIONS

A

completely
adjusted
and
serviced
carburetor
will

provide
the

engine
with

proper
mixture

at
all

speeds

Periodical

overhauling
which
cleans

all

components
and

passages
will

recover
the

originally
designed
performance

producing
the

engine
with

proper
gasoline
and
air
ratio
at

all

speeds
Passages
and
holes
of
the
carburetor
must
be

cleaned

carefully
Use

only
carburetor
solvent
and
com

pressed
air

to
clean
aU

passages
and

discharge
holes
Never

use
wire
or
other

pointed
tool
otherwise

accurately

calibrated
carburetor

will
be

affected

Removal

Remove
the

air
cleaner

2

Disconnect
the
fuel
line
vacuum
line
automatic

choke
harness
and
anti
dieseling
solenoid
harness
from

carburetor

3

Remove
the
throttle
lever

4
Remove
four

nuts
and

washers

retaining
the

carbuTe

tor
to
the

manifold
if

necessary

5
Lift
the
carburetor
and
remove
from
the

manifold

6
Remove
and
discard
the

gasket
used

between
the

carburetor
and
manifold

Disassembly

The
main

jets
and
needle
valves
on
both

primary
and

secondary
sides
are

accessible
from
outside
of
the

carbure

tor
for

disassembly

2
Remove

throttle
return

spring

3
Remove

pump
lever
shaft
take

out

pump
lever

and

pump

connecting
rod

4
Remove

rubber

pipe
from
choke

piston

5

Loosen
off
bolts

securing
servo

diaphragm
in

posi

tion
take
out

diaphragm

6

Back
off
total
of
five
bolts
which
hold
choke
in

position
and
remove
rods
of
starter

system
take
out

choke
chamber

In

removing
chamber
exercise
care
to
avoid

damaging

float

EF
19
ilia

Fig
EF
32

Removing
choke
dwmherand

seroo

diaphragm

7
The

primary
and

secondary
emulsion

tubes
can

be

disassembled

by
removing
the

main
air
bleeds
on
the

individual
sides

In

removing
injector
weight
piston
return

spring
and

ball
care
should
be
excercised
to

prevent
them
from

being

scattered
and
lost

OQ

fI

Fig
EF
33

Removing
emulsion
tubes

8
To

check
the

accelerator

pump
the

pump
cover
is

removed
Be
careful
not

to
lose
the

return

spring
and
inlet

valve
ball

provided
at
the
lower

part
of
the

piston

during

disassemb

ly

Removal
of

bi
metal
cover
is
a

simple
matter
of

removing
three
set
screws

When
it

becomes

necessary
to
take

out
float

pull
shaft

from
float

Note
Under
no

circumstances
should
bi
metal
be
moved

with
excessive
force
since
this

may
cause
a

perma

nent
set
in
bi
metal

making
starting
difficult

ENGINE

Y
Q

0

Fig
EF
34

Disassembling
accelerator

pump
and

hi
metal
cover

1

EC013

Fig
EF
35

Removing
throttle
chamber

9

The
throttle
chamber
can
be
detached
from
the
float

chamber

by
removing
three
set
screws

Do
not
remove
anti

dieseling
solenoid
unless
it
is

necessary
to

change
If

necessary
refer
to
the
item
of

Anti

dieseling
solenoid

page
EF

12

10
It
is

preferable
to
leave

throttle
valve

intact
unless

otherwise

required
If

throttle
valve

must
be
disassembled

to
remedy
a
defect

secondary
throttle
valve

must
be

installed
with

gap
to
be
free

Otherwise

stable

idling
and
slow

speed
performance

will
not
be

obtained
I

o

rJ

01

o

o

Fig
EF
36

Removing
throttle
valve

II
In

disassembling
and

reassembling

interlocking

links
take

care
so
that
each

linkage
has
a
smooth
action

and
that

it
is
not
fitted
in

any
forced

position

Cleaning
and

inspection

Dirt

gum
water
or
carbon
contamination
in
or
on
the

exterior

moving
parts
of
carburetor
are
often

responsible

for

unsatisfactory
performance

For
this
reason
efficient
carburetion

depends
upon

careful

cleaning
and

inspection
while

servicing

1
Blow

aU

passages
and

castings
with

compressed
air

and

blow
off
all

parts
until

dry

Note
Do
not

pass
drills
or
wires

through
calibrated

jets

or

pssages
as

this

may
enlarge
orifice
and

seriously

affect
carburetor
calibration

2
Check
all

parts
for
wear

Replace
worn

part
Especial

ly
the

following
matters
should
be
noted

I
Check
float
needle
and
seat
for
wear

Replace
the

assembly
if
worn

2

Check
the
throttle
and

choke
bores
in

throttle

body

and

cover

casting
for
wear
or

out
of
round

3

Inspect
idle

adjusting
needles
fur
burrs
or

ridges

Replace
as

required

3

Inspect
gaskets
to
ensure
that

they
do
not

appear

hard
or

brittle
and
that
the

edges
are
not
turned
or

distorted
If

any
such
condition
is

detected

they
must
be

replaced

4

Check
fIlter
screen
for

clogging
Clean
and
if
it
is

distorted
or
remains

plugged
replace

EF
20

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

ENGINE

Choke

unloader
clearance

carburetor

body
C

between
choke
valve
and

mm
in

Bi
metal
resistance

ohms
2
01

0
07911

8

6t09
0

Accelerator

pump

Injector
hole

Return

spring

Fuel

pressure
mm
in

g
mm

Ib
in

kg
cm
2

psi

kg
lb
0
5

0
0197

78
I
I

0
18
2
6

Manual
transmission

Automatic
transmission
Weight
2
8
6
2

2
9
6
39

Example
1
215

represents
215
100
2
15

mm
0
0846
in

diameter

TROUBLE
DIAGNOSES

AND
CORRECTIONS
There
are
various
causes
of

engine
tarubles
It

some

times

happens
that
the

completely
effective

carburetor

seems

apparently
to
have

some
troubles

when
electric

system
is

defective
Therefore
whenever
the

enigne
has

troubles
electric

system
must
be

checked
first
before

adjusting
the

carburetor
In
the

following
table
the

symptoms
and

causes
of

carburetor
tarubles
and
remedies

for
them

are
listed

to

facilitate

quick

repairs

Troubles

Possible
causes
Remedies

Overflow
Dirt

accumulated
on

needle
valve
Clean
needle
valve

Fuel

pump
pressure
too

high
Repair

pump

Needle
valve
seat

improper
Lap
or

replace

Excessive

fuel

consumption
Fuel
overflows
See
above

Each
main
air

bleed

clogged
Clean

Gauge
plate

adjustment
incorrect

Correct

adjustment

Choke
valve
does

not

open

Adjust

Outlet
valve
seat

of
accelerator

pump
im

proper
Lap
or

replace

Linked

opening
of

secondary
throttle
valve

too

early
Adjust

Power

shortage
Each
main

jet
clogged
Clean

Each
throttle
valve

does
not

fully
open
Adjust

Fuel

pump
operated
improperly
Repair

EF
22