1973 DATSUN B110 Service Repair Manual

ENGINE

Adjusting
carburetor
idle

rpm

mixture
ratio

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
NO

position
for
automatic
transmission

4
Check

ignition
timing
if

necessary
adjust
it
to
the

specifications

Ignition
timing
SO

800

rpm

S

Adjust
idle

adjusting
screw
so
that

CO

percentage
is

1
5
t
O
S

6

Repeat
the

adjustments
as
described
in

steps
3

and

S

above
so
that

CO

percentage
is
I
i
t
O

S
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

CO

percentage

with
lever
in

D

position
6S0

I
S
t
O
S

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
idle

adjusting
screw

completely
to
avoid

damage
to

the

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

Idle

adjust

ing
screw

3
Idle

limitter

cap

4

Stopper

Fig
ET
13
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
re

adjust
it

at

the

time
of

installation
To

adjust
proceed
as
follows

L
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

CO
RICH

direction

CARB
STOPPER

J

Z

3
8
ROTATION

0

IDLE
LIMITER
CAP

0
to
RICH

CO
LEAN

Fig
l
T
14

Setting
idle
limiter

cap

ET
8

EMISSION
CONTROL
AND

TUNE
UP

Checking
and

adjusting
dash

pot

automatic
transmission
model

only

Check

operation
of
dash

pot
It
should

not
be
cracked

or

bound
It

is
also
essential
to
check
to
be
certain

that
it

is
in

correct

adjustment

L
Check
to
be
sure
that
dash

pot
contacts

stopper
lever

when

engine
speed
reaches
1
900

to
2

000

rpm

2

Engine
should
be
slowed
down
from
3

000
to
1

000

rpm
within
a
few

seconds

Readjust
dash

pot
or

replace
it
with
a
new
one
if
it

fails

to
meet

the
above

conditions

Checking
carburetor
return

spring

Check
throttle
return

spring
for

sign
of

damage
wear

or

squareness
Discard

spring
if
found
with

any
of
above

excessively
beyond
use

Checking
choke
mechanism

choke
valve
and

linkage

1

Check
choke
valve
and

mechanism
for
free

operation

and
clean
or

replace
if

necessary

A

binding
condition

may
have

developed
from

petro

leum

gum
for
motion
on
choke
shaft
or

from

damage

2

Check
bimetal
cover

setting
position
The

index
mark

of
bimetal
cover
is

usually
aligned
at
the

middle

point
of

the
scale

Note
When
somewhat
over
choked
turn
bimetal

caver

clockwise

slightly

3
Prior
to

starting
check
to
be
sure
that

choke
valve

closes

automatically
when

pressing
down
on
accelerator

pedal

Should
it
fail
to
close

automatically
the
likelihood
is

that
fast
idle
cam
is
out
of

proper

adjustment
or

that

bimetal
is

not

properly
adjusted
calling
for

adjustment

Refer
to
Carburetor
in
Section
EF

Page
EF
15
Checking
anti

dieseling
solenoid

If

engine
will
not

stop
when

ignition
switch
is
turned

off

this
indicates

a

striking
closed
solenoid
valve

shutting
off

supply
of
fuel
to

engine
If
harness
is
in

good

condition

replace
solenoid
as
a
unit

To

replace
proceed
as
follows

Removal

and
installation

of
anti

dieseling
solenoid

Removal

Solenoid
is
cemented

at

factory
Use

special
tool

STl
91
50000
to
remove
a

solenoid

When

this
tool
is

not
effective
use
a

pair
of

pliers
to

loosen

body
out
of

position

lnstalltion

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
carbu

retor
more
than
12

hours
without

operation

3

After

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
I
n

installing
valve
use
caution
not
to
hold

body
directly
Instead

use

special
tool

tighten

ing
nuts
as

required

ET
9

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

EMISSION

CONTROL
AND
TUNE
UP

Ignition
switch

0

Speed
switch

Ignition
switch

6

Transmission
A12

Engine
with
Manual
Transmission

l

Battery

J

Below
10

mph

switch

ON
To
throttle

opener

Servo

diaphragm

Needle
valve

To
air
cleaner
To

intake

manifold

f

Vacuum
control

valve

p

Throttle

opener

noid

ON
Car

speed
below
16
km
h
10
MPH

OFF

Car

speed
above
16
km
h
10
MPH

A12

Engine
with
Automatic
Transmission

Inhibitor
switch
1

J
Battery

To
intake

manifold

t

ET
11
OFF
ON

Fig
BY
16

Schematic

drawing
of
throttle

opener
system
To
throttle

opener

Servo

diaphragm
Vacuum
control

valve

P

Throttle

t
opener

solenoid

7
7

ON
transmission
in
N
and
P

positions

OFF
Transmission
in
0

position

ENGINE

Carburetor

1
1

U

Y

d
V

I
j

0

j

hl
Intake
manifold

@

Ff

To
air
cleaner

1
Valve

2

Diaphragm

3

Altitude
corrector

4

Vacuum
adjusting
screw

5
Filter

6
Manifold
vacuum
hose

7

Adjusting
screw

8
Primary
throttle
valve
Th
rattle

opener
solenoid

Fig
ET
17
Throttle

opener
control

system

ET
12

EMISSION
CONTROL
AND

TUNE
UP

Operation
manual
transmission

equipped
model

The

operation
of
the
solenoid
is

by
means
of
the

movement
of

the

speedometer
needle

When
vehicle

speed
falls
below
16

km
h

10

MPH
the

needle
movement

produces
a

signal
which
in
turn
is

amplified
to
actuate
the

solenoid

I
Vehicle

speed
Speed
Throttle

Throttle

switch
opener

opener

solenoid

Below
16
km
h
Not

10
MPH
ON
ON

actuated

Above

16
km
h

OFF
OFF

Actuated

10
MPH

Operation
automatic
transmission

equipped
model

The

solenoid
is

operated
by
an
inhibitor

switch
which

actuates
the
solenoid

only
when
the
transmission
is

placed
in

the
N
or
P

position

c
fil

rn

AT057

Fig
ET
18

Inhibitor
switch
installation

Checking
and

adjusting
throttle

opener

Principally
it
is

unnecessary
to

adjust
the
throttle

opener
however
if
there
is

any
requirement
the

adjust

ment

procedure
is
as

follows

Prepare
the

following
tools

1
A

tachometer
to
measure
the

engine

speed
and
a

screwdriver

2
A
vacuum

gauge
and

connecting
hose

ET
13
Notes
a
A

quick

response
boost

gauge
such

as
Bour

don
s
tube

type
is
recommended
Do
not

use

mercury
manometer

b

Any
special
tools

are
not

required

Warming

up

Warm

up
engine
until
it
is
heated

to

operating

temperature
Make
sure
that

the
automatic
choke
valve

is

fully
open

Connecting
vacuum

gauge

Disconnect
vacuum
hose
between
intake

manifold
and

automatic

temperature
controlled
air

cleaner
install

a

vacuum

gauge
to
intake
manifold
connector
as
shown

in

Figure
ET

19

1
Intake
manifold

2
Connector

3
Vacuum

gauge
4
Vacuum
control
valve

5
Throttle

opener

solenoid

Fig
ET
19

Adjusting
throttle

opener

Deenergizing
solenoid

Disconnect
throttle

opener
and
vacuum

cutting
valve

solenoid
harness

and
free
solenoid

Adjusting
idling

Check
the

engine
idling
Adjust
if

necessary

Engine
idling

rpm
Idling

timing

I
CO

degree

SO

BTDC

I
L51c0
5

SO

BTDC

I
I
S
1c
0
5
M
T
Car

A
TCar
800

6S0
in
D

ENGINE

Adjusting
throttle

opener
setting
engine
speed

1
Connect
servo

diaphragm
vacuum
hose

directly
to

intake
manifold

connector
without

laying
through

vacuum
control
valve

2
With

negative
pressure
vacuum
in

intake
manifold

servo
diaphragm

operates
and

thus
the

primary

throttle
valve

is

opened
When

servo

diaphragm
nor

mally
operates

engine
speed
rises

reaching
1
650

to

1

850

rpm
When

engine
speed
is

not
within
this

range

turn

adjusting
screw
as

necessary
See

Figure
ET
20

l
When

engine
speed
is
lower

than
the

prescribed

range
turn

adjusting
screw

clockwise

2
When

engine
speed
is

higher
than
the

prescribed

range
turn

adjusting
screw

counterclockwise

Upon
completion
of
the

adjustment
set

adjusting

screw
lock
nut

secwely
making
sure
that

engine
speed

is
in

the

prescribed

range

@
II
I
AdJustmg
screw

2
Lock

nut

Fig
ET
20
Servo

diaphragm
adjusting
screw

Servo

diaphragm

Servo

diaphragm
stroke

Link

EC015
3

Disconnect
servo

diaphragm
vacuum

hose
from

intake

manifold
and
connect

it
to

vacuum
control

valve

Connect

vacuum
hose
of

control

valve
to
intake

manifold
normal

piping

Racing

Place
shift

lever
in

neutral
for

MfT
or
N

or
p

for

AlT
Raise

engine
speed

up
to

approximately
3

000

rpm
under
no
load
and

close
throttle

valve

by

releasing

it

from
hand

Examine

engine
speed
to
see

whether
it
falls
to

idling

speed

I
When

engine
revolution
rails
to

idling
speed

See

Figure
ET
24

The

primary
throttle

valve
is

opened
by
the
link

connected

to
it

When
the

engine
speed
is
increased

to

approximately
3

000

rpm
and

lowered

natually

from
this

speed

changes
in

servo

diaphragm
link

stroke
manifold

vacuum
and

en
ine

speed
are
as

shown
in

Figure
ET
21

o

u

u

0

2
Se
o

diaphragm
link
stroke

I
u

2

Full

0

o

Intake
manifold
vacuum

u

c

E

c

O
3000

c

e

Engine
speed

2000
g

i

c

1000

T
j

Time

second

Fig
ET
21

Changes
in
servo

diaphragm
link
stroke
intake

manifold
vacuum
and

engine
speed

ET
14

EMISSION
CONTROL
AND

TUNE
UP

As

the

engine
speed
lowers

negative
pressure

generated
in
the
intake

manifold
also
lowers
How

ever

dropping
of

negative

pressure
in
the

intake

manifold
is

suspended
for
a
few

seconds

by

op

erating
the
servo

diaphragm
and

vacuum
control

valve

In
the

graph
shown
in

Figure
ET
21

curve
is

comparatively
flat

Thus
He
emission

emitted

under
these
conditions

is
controlled

by
these

devices

The

comparatively
flat

portion
of
the

curve
shown
in

Figure
ET

21
is
called

Operating
pressure

Operating
pressure

changes

depending
on
altitude

and

thus

servo

diaphragm
and
control

valve

opera

tions

are

adjusted
in

coincidence
with
the

altitude

at

which
the

vehicle
is

driven

automatically
The

graph

shown
in

Figure
ET
22

indicates

change
in

operating

depression
for

changes
in

atmospheric
pressure
and

altitude

c

I
I

E
I

I
E

E
c

0

s

I
T

30

750

600
24

A
29

23
28

700

550
22
27

21
26

650

500

20
25

l

0

c

0

o
19
JOr

0

1
01

to

4

t

C

4

22

21

20
a

5

24

600

0

o

E
450

18
23

17

550

400
16

15

500

350
14

19

13
F

18

450

300
12

o
1000
2000
3000

4000
5000
6000

It

I

0
5
1
0
1
5
2
0
km

Altitude

Fig
EY
22

Changes
in

operating
pressure
for

changes
in

atmospheric

pressure
and
altitude

ET
15