engine DATSUN PICK-UP 1977 Service Manual

Engine
Fuel

1
L

if

1

Pump
injector

2
Piston

3

Spring

4

Weight

5

Damper
spring

6
Piston
return

spring

7

Inlet
valve

8
Outlet
valve

EF023

Fig
EF
26
Acceleration

mechanism

Power

valve
mechanism

SECONDARY
SYSTEM

The

power
valve

mechanism
so

called
vacuum

piston

type
utilizes

the

vacuum
below
the
throttle
valve

When
the

throttle
valve
is

slightly

opened
during
light
load

running

high

vacuum
is

created
in

the
intake
mani

fold
This

vacuum

pulls
the

vacuum

piston
upward

against
the

spring

leaving
the

power
valve
closed
When

the
vacuum
below
the
throttle

valve
is

lowered

during
full
load
or

accelerat

ing

running
the

spring

pushes
the

vacuum

piston
downward

opening
the

power
valve
to
furnish

fuel
Secondary
main

lIYlltem

pulled
out

through
the
main

nozzle

into
the
small
venturi

Due
to
the

double
venturi

of
the

secondary
system
the

higher

velocity

air

current

passing
through
the
main

nozzle

promotes
the
fuel
atomization

The
structure
is

almost
the

same
as

the

primary
side
The

secondary
main

system
is

a

Stromburg
type

Fuel
air
mixture

produced
by
the

functions
of
the
main

jet
main
air

bleed

and
emulsion
tube
in

the
same

manner
as
in

the

primary
system
is

11
1

I

1

1

Primary
vacuum

port

2

Secondary
vacuum

port

3

Diaphragm
chamber

cover

of

Diaphragm

spring

S

Diaphragm

6

Secondary
throttle

valve

7

Primary
theo
nle

valve
lWll
I

1
11

l
v
1

Vacuum

piston

2

Power

valve

ET02
a

EF
512

Fig
EF
27
Sectional

view

of

po
r

valve

Fig
EF
28
Full
throttle
al

high
peed

EF

16

Step
system

The

construction
of
this

system

may

correspond
to
the

idling
and
slow

system
of

the

primary
system

Tlris

system
aims

at
the

proper

filling
up
of
the

gap
when

fuel

supply

is
transferred
from
the

primary
system

to
the

secondary
one
The

step
port
is

located
near
the

secondary
throttle

valve

edge
in
its

fully
closed

state

Secondary
switchover
mechanism

The

secondary
throttle
valve
is

linked
to
the

diaphragm
which
is

actuated

by
the
vacuum

created
in
the

venturi
A

vacuum

jet
is

provided
at

each
of
the

primary
and

secondary

venturies
and
the

composite
vacuum

of
these

jets
actuates
the

diaphragm

As
the

linkage
causes
the

secondary

throttle
valve
to
close
until
the

prima

ry
throttle
valve

opening
reaches

ap

proximately
500
fuel

consumption

during
normal

operation
is

not
exces

sive

During
high
speed
running
as

shown
in

Figure
EF
28
as
the

vacuum

at
the
venturi
is
increased
the
dia

phragm
is

pulled
against
the

diaphragm

spring
force
and
then

secondary
throt

tie
valve
is

opened

The
other

side

during
low

speed

running
as
the

primary
throttle
valve

opening
does
not
reach
500
the

secondary
throttle
valve
is

locked
to

close

completely
by
the

locking
arm

which
is
interlocked
with

primary

throttle
arm

by
linkage

When
the

primary
throttle
valve

opening
reaches
wider

position
than

500
the

secondary
throttle
valve
is

ready
to

open
because
the

locking

arm
revolves
and
leaves
from
the

se

condary
throttle
arm
Engine
Fuel

HI
h

speed
circuit

The
high

speed
circuit

improves

high
engine
output
performance

during
high

speed
driving

This
circuit

operates
only
when

driving
at

high
speed
It
consists
of
a
richer

jet
high
speed
enricher
air

bleed
and
richer
nozzle
When
the

velocity
of
suction
air

flowing

through

the

carburetor
secondary
bore
in

creases
additional
fuel
is
drawn

out
of

the

richer
nozzle

@
2

EF234

Secondary
I

Richer

jet

2

High
speed
enricher

air
bleed

3
Richer
nozzle
Primary

Fig
EF
29

High
speed
circuit

ANTI
DIESELlNG
SYSTEM

is

brought
into

operation
shutting
off

the

supply
of
fuel
to
the
slow
circuit

The

following
figure
shows
a

see

tiorial
view

of
this
control
The
carburetor
is

equipped
with
an

anti

dieseling
solenoid
valve

As
the

ignition
switch
is
turned
off
the
valve

EF230

@

l
CD

1

1
g

@eI

1
Anti
dieseling

solenoid
va1

2

Ignition
switch

3

Battery

Fig
EF
30
Schematic
drawing
of
anti

dieseling
sydtm

EF
17

FLOAT
SYSTEM

There
IS

only
one

float
chamber

while
two
l

arburetor

systems
primary

Jnd

st
l

ondary
are

provided

Fuel
fed
from
the
fuel

pump
flows

through
the
filler
and
needle

valve
into

the
flo
t
chamber
A

constant
fuel

level

is
maintained

by
the
float
and

needle
valve

Because
of

the
inner
air

vent

type

of

the
float
chamber
ventilation
the

fuel

consumption
will
not

be
in

fluenced

by
some
dirt
accumulated
in

the
air

deaner

The
needle
valve

includes

special

hard
steel
ball

and
will
not

wear
for
all

its

considerably

long
use
Besides
the

inserrion

of
a

spring
wiU

prevent
the

flooding
at

rough
road

running

BOOST

CONTROLLED

DECELERATION
DEVICE

B
C
D
D

A

Boost
Controlled
Deceleration

Device
B

C
D

D
serves
to

reduce
the

hydrocarbons

He
emitted
from
en

gine
during
coasting

The

high
manifold
vacuum

during

coasting

prevents
the
mixture

from

complete
combustion

because
of
the

reduced
amount
of
mixture

per
cyl

inder

per
rotation

of

engine
with
the

result
that

a

large
amount
of

hydrocar

bons
is

emitted
into
tile

atmosphere

The
B

C
D
D
has
been

designed
to

correct

this

problem

It

opern
tes

as
follows

when
the

manifold

vacuum
exceeds
a

pre
Engine
Fuel

determined

value
the

B
C
D
D
intro

duces

an
additional
mixture

of

opti

mum
mixture
ratio
and

quantity
into

the

manifold

by

opening
a

separate

mixture

passage
in
the

carburetor

Complete
combustion

of
fuel
is
assist

ed

by
this
additional
mixture

and
the

amount

of
H
C

contained
in

exhaust

gases
is

dramatically
reduced

During
the

transition

period
from

coasting
to

idling
the
transmission

produces
a

signal
which
turns
on
the

vacuum
control

solenoid
valve
As
this

takes

place
the
valve
is

lifted
off
its

seat

opening
the

vacuum
chamber
to

the

atmosphere
The
mixture

control

valve
is
then

closed

returning
the

engine
to
the

predetermined
idling

speed

On
manual

transmission
models

this

system
consists

of
B
C
D
D

vacuo

urn
control

solenoid
valve

speed
de

tecting
switch
and

amplifier

On
automatic

transmission

models

it
consists

of
B
C
D
D

vacuum
con

trol

solenoid
valve

and

inhibitor

switch

B
C
D
D

operation

Diaphragm
I

Qj
monitors
the

mani

fold

vacuum
and

when
the

vacuum

exceeds
a

pre
fetermined
value
acts
so

as

to

open
the

vacuum
control
valve

@
This
causes

the
manifold

vacu
urn

to
be

introduced
into
the

second

vacuum
chamber
and

actuates
dia

phragm
ll@

When

diaphrngm
II

operates
the

mixture

control
valve

@
opens
the

passage
and
introduces
the
additional

mixture
into

the
manifold

EF

18
The
amount
of

the
mixture

is
con

trolled

by
the

servo
action

of
the

mixture
control

valve

CID
and

vacuum

control

valve

@
so

that

the
manifold

vacuum

may
be

kept
at
the

pre

determined

value

The
amount

of
mixture

depends

mainly

upon
the

coasting
air
bleed

II@
while
the
mixture
ratio

is
deter

mined

by
the

coasting
jet

@
and

coasting
air
bleed

@
See

Figure

EF
31

Vacuum

control
solenoid

valve

operation

Manual

transmission
models

The

vacuum
control

solenoid
valve

is

con
troDed

by
a

speed

detecting

switch
that
is

actuated

by
the

speed

ometer
needle

As
the
vehicle

speed
falls

below
10

MPH
this
switch
is
activated

pro

ducing
a

signal
This

signal
actuates
the

amplifier
to

open
the
vacuum
control

solenoid
valve

Automatic

transmission
models

When
the

shift
lever
is
in
N

or

P

position
the
inhibitor
switch

mounted
on
the
transmission

turns
on

to

open
the
vacuum

control
solenoid

valve

I
Air

jet

2

Diaphragm
II

3
Mixture
control
valve

4

Coasting
air

bleed
II

5
Mixture
air

passage

6

Secondary
baHel

7
Intake
manifold

8
Boost

passage

9
Vacuum
control
solenoid

valve

10
Vacuum
control
valve

II

Diaphragm
I
Engine
Fuel

12

Secondary
main

jet

13

Coasting
jet

14

Coasting
air
bleed
I

15
Inhibitor
switch
N

P

ON
for
automatic

transmission

16

Amplifier

1
7

Speed
de

tecting
swi
tch
below

10
M
P
H
ON

for
manual

transmission

1

W
j

I

t

i
J

l

J
18

Ignition
switch
CID

1
1

fI3
6

@
I

r
101

@
i

r

@

JJ

Note
Broken
line

applies
only
to
Automatic
Transmission

I

Ignition
switch

2

Amplifier

3

Speed
detecting
switch
below

10
M
P

H
ON
for
manual

transmission

4
Inhibitor
switch
N
p

ON
for
automatic

transmission

5
Solenoid
valve

6
Vacuum
control
valve

7
Altitude

corrector

LlJ

I

I

l

f

L8
J

l
EF231

Fig
EF
31
Schematic

drawing
of
B
C
D
D
Non

California
models

1

J
ru

I

r

lJ

i7

I
To
intake

manifold

To
air

cleaner

E
F235

Note
Broken
line

applies
only
to
Automatic
Transmission

Fig
EF
32
Schematic
drawing
of
RC
D
D

California
models

EF
19

ELECTRIC
AUTOMATIC

CHOKE

An
electric
heater
wanns
a
bi
metal

interconnected
to
the
choke
valve
and

controls
the

position
of
choke
valve

and
throttle
valve
in
accordance
with

the

time

elapsed
the
warm

up
condi

tion

of
the

engine
and
the

outside

ambient

temperature

When
outside
ambient

temperature

is

above

operating
temperature
the

automatic

choke
control
serves
to
fur

ther
reduce
exhaust

gasemission

during
warm

up
by
automatically

selecting
one
of
the
two

choke

opera

tion
modes
fast

acting
or
slow

acting

Slow

acting
choke

operation

When
ambient

temperature
is
low

electric
current
flows

through
the

automatic

choke

relay
to
the
P
T
C

heater
A

and

gradually
warms
the

bi

metal
This
causes
the
choke
valve

to

open
slowly

Fast

acting
choke

operation

When
ambient

temperature
is

high

the
bi
metal
switch
is
in

on
This

causes
electric

current
to
flow

through

the
automatic

choke

relay
to
the

P

T
C
heater
A
and
heater

B
result

ing
in

quick

opening
of
the

choke

valve

r

@@

r

@
Engine
Fuel

The

construction
and

function
of

each

part
of

this
carburetor
are
as

follows

l
Bi
metal
and
heater
in
choke

cover

Electric
current

flows

through
the

ttea
r
as

t
le
engine
tl

1
SI
nd
war

the
bi
metal

The
deflection
of
the

bi
metal
is
transmitted
to
the
choke

valve

through
the
choke

yalve
lever

2
Fast
idle
cam

The
fast
idle

cam
determines
the

opening
of
the
throttle
valve

so
that

the

proper
amount
of

mixture
cor

responding
to
the

opening
of
the

choke
valve
will
be
obtained
The

opening
of
the

choke
valve
is

depend

ent

upon
the
warm

up
condition
of

the

engine

3

Fast
idle

adjusting
screw

This

screw

adjusts
the

opening
of

the
throttle

valve
of
the
fast

idle
earn

4
U

nloader

When

accelerating
the

engine
during

the

warm

up
period
that
is

before
the

choke

valve

opens
sufficiently
this

unloader
forces

the
choke
valve

open
a

liUle
so

as
to
obtain

an

adequate

air
fuel

mixture

5

Vacuum

diaphragm

After

the

enginThas
been

started

by
cranking
this

diaphragm
forces

the

choke
valve

open
to
the

predetermined

extent
so

as
to

provide
the

proper

air
fuel
ratio

6
Bi
metal

case
index
mark

The
bi
metal

case
index
mark
is

used

for

setting
the

moment
of
the

D

Il

EF232

1

Alternator

2
Automatic
choke

relay

3
Automatic
choke
cover

4
P

T
C
heater
A

5
Bi
metal
switch

6
P

T
C
heater
B

7
Bi
metal

8
Choke
valve

Fig
EF
33
Schematic

drawing
of
electric
automatic
choke
heater

EF

20
bi
metal
which

controls
the
air

fuel

mixture
ratio

required
for

starting

DASH
POT

SYSTEM

These
carburetors
are

equipped

with

a
dash

pot

interl
ked
wi
h

the

primary
throttle

valve

through
a
link

mechanism
The

dash

pot
is
intended

to

prevent

engine
stall

resulting
from

quick
application
of
the
brake
or

from
the

quick
release
of
the
accele
ra

tor

pedal
after

treading
it

slightly

In

such
a

situation
a
throttle
lever

strikes

against
the
dash

pot
stem
and

makes
the

primary
throttle
valve
close

gradually
thus

keeping
the

engine

running

ALTITUDE
COMPENSATOR

California
models

The

higher
the
altitude
the
richer

the
air

fuel
mixture
ratio
and
there

fore
the

higher
exhaust

gas
emissions

even

though
the

engine
is

properly
ad

justed
for
low

altitude

driving

The
altitude

compensator
is

design

ed

to
meet
EiiriSSion
S13ndards
for

driving
in
both
low
and

high
altitudes

At

high
altitudes
additional
air
is

sup

plied
to
the
carburetor

by
the
altitude

compensator
When
the
altitude

com

pensator
lever

is
set
at
H
air
is

conducted

through
an
air

passage
to

the

carburetor
The
air

passage
is

closed
when
the
lever

is
set
at
L

H

L
Lever

When

operating
the
H

L
lever
fol

low
these

instructions

H

position

Should
be
used
for

general
driving

in

those
areas

designated
by
law

as

High
Altitude
Counties

L

position

For
use
outside
those
areas

desig

nated
as

High
Altitude
Counties

Notes

a

The
idle

rpm
and
CO

vary
accord

ing
to
the
altitude
Therefore

they

should
be

properly
adjusted
when

the

position
of
the
H
L
lever
is

changed

EF729

ADJUSTMENT

AND
INSPECTION

CARBURETOR
IDLE
R
P
M

AND
MIXTURE
RATIO

Cautions

3
On

automatic
transmission

equi

ped
models
check
should
be

per

formed
in

the
0

position

Be
sure
to

engage

parking
brake
and

to
lock
both
front
and

rear
wheels

with
wheel
chocks

b

Keep
your
foot
down
on
the
brake

pedal
while

depressing
the
accelera

tor

pedal
Otherwise
vehicle

surges

forward

dangerously

Notes

a
00
not

attempt
to
screw
the
idle

adjusting
screw
down

completely

Ooing
so
could
cause

damage
to

tip

which
in
turn
will
tend
to
cause

malfunctio11ll

b
If
idle
limiter

cap
obstructs

proper

adjustment
remove
it

To
install
idle
limiter

cap
refer
to

Idle
Limiter

Cap

c
After
idle

adjustment
has
been

made
shift
the
lever
to
the
N

or

P

position
for
automatic
trans

mission

d
When

measuring
CO

percentage
in
Engine
Fuel

b
Counties
1

219
m
4
000
ft
or

more
above
sea
level
have
been

designated
by
law
as

High
Altitude

Counties
For

further
details
refer

to
1977
OATSUN
PICK
UP
Service

Bulletin
Pub
No
257

0

I
Air
cleaner

rID
mOl

If
Low
altitude

Ll

n
n

L
n

Fig
EF
34

sert

probe
into
tail

pipe
more
than

40
em

15
7
in

CO
Idle

adjustment
with

CO
meter

Idle
mixture

adjustment
requires

the
use
of
a

CO
meter

especially
for

California
models
When

preparing
to

adjust
idle
mixture
it
is

essential
to

have

the
meter

thoroughly
warmed

up

and

calibrated

I

Check
carburetor

pipes
for

proper

connection

2
Warm

up

engine
until
water

tem

perature
indicator

points
to
the
middle

of

gauge
The

procedure
to
warm

up

engine
is
not

specifically
recom

mended
Either

driving
vehicle
or

oper

ating
engine
at

no
load
will

be

good

3
Make
sure
that
water

tempera

ture
indicator

points
to
the
middle

Further

keep

engine
running
at
about

2
000

rpm
for

about
5

minutes
with

out

applying
load
to

engine
in

order
to

stabilize

engine
condition

Engine

hood
should
be

open

4
Run

engine
for
about

10
minutes

at

idling
speed
Ouring
this
10

minutes

proceed
as
described
in

steps

5

to
9
below

5
Remove
air

hose
between
3

way

connector
5

way
connector
for
Cali

fornia
models
and
air

check
valve
as

EF
21
shown
in

Figure
EF
35

Plug
the
dis

connected
hose

to

prevent
dust

from

entering

0

o

EF259

Fig
EF
35
Disconnecting
air
hose

from
air
check
valve

6
Race

engine
I
500

to
2
000

rpm

two
or
three
times

under
no
load
then

run

engine
for
one
minute
at

idling

speed

7

Adjust
throttle

adjusting
screw

until

engine
is

at

specified
speed

Engine
speed

Manual
transmission

750

rpm

Automatic
transmission

in
0

position

650

rpm

8
Check

ignition
timing
If
neces

sary
adjust
it
to

specifications

This

operation
need
not
be
carried

out
at
1

600
Ian
1

000
miles
service

Ignition
timing

Manual
transmission

120
750
rpm
Non
California

100
750

rpm
California

Automatic
transmission

in
0

position

120

650

rpm

9
At

about
10
minutes

after

engine

is
run

at

idling
speed
adjust
idle

adjusting
screw
so

that
CO

percentage

is
at

specified
level

CO

percentage

Manual
transmission

2
t
l

at
750

rpm

Automatic

transmission

in
0

position

2
t
I
at
650

rpm

10

Repeat

procedures
as
described

in

steps
6

7
and
9
above

so
that
CO

percentage
is
at

specified
level
Check

ing
idle
CO
in

step
9
can

be
carried
out

right
after

step
7

II
Race

engine

1
500
to
2

000

rpm
two
or
three

iimes
under
no

load

and
make

sure
that

specified
CO

per

centage
is
obtained

12

Connect
air

hose
to
air

check

valve

If

engine
speed
increases

readjust
it

to

the

specified
speed
with
throttle

adjustingsqew

CO
idle
edJustment
without

CO
meter

If
CO

meter
is
not

available
the

following
procedures
may
be
used

L
Check

carburetor

pipes
for

proper

connection

2
Warm

up
engine
until
water

tem

perature
indicator

points
to
the

middle

of

gauge
The

procedure
to
warm

up

engine
is
not

specifically
recom

mended
Either

driving
vehicle
or

oper

ating
engine
at

no
load
will

be

good

3
Make

sure
that

water

temperature

indicator

points
to
the
middle

Further

keep
engine
running
at
about
2

000

rpm
for
about
5

minutes
without

applying
load
to

engine
in
order

to

stabilize

engine
condition

Engine

hood
should
be

open

4
Run

engine
for

about
10
minutes

at

idling

speed

During
this

10

minutes

proceed
as

described
in

steps

5
to

9
below

5

Remove
air

hose
between
3

way

connector
5

way
connector

for
Cali

fornia
models
and
air

check
valve

shown
in

Figure
EF

35

Plug
the
dis

connected
hose

19
prevent
dust
from

entering

6
Race

engine
1
500
to
2
000

rpm

two
or

three
times
under

no
load
then

run

engine
for

one
minute

at

idling

speed

7

Adjust
throttle

adjusting
screw
so

that

engine
speeds
are

as
indicated

below

Engine
speed

Manual
transmission

815

rpm

Automatic
transmission

in
D

position

670

rpm

8
Check

ignition
timing
if
neces

sary

adjust
it

to
the
value

required
by

specifications
This

operation
need

not

be
carried
out
at
1

600
km
1

000

miles
service

9
At
about

10
minutes
after

engine
Engine
Fuel

is

run
at

idling

speed
adjust
idle

adjusting
screw
until
maximum

rpm
is

obtained

10

Repeat
procedures
as
described

in

steps
6
7
and

9
above

until

engine

speed
at
best
idle
mixture
is
815

rpm

for

manual
transmission

models
and

670

rpm
for
automatic
transmission

models

in
D

position
Adjustment

in

step
9
can
be
carried
out

right
after

step
7

11
Turn
the

idle

adjusting
screw

clockwise
until

engine
speed
drops
off

below

specified

rpm

Engine
speed

drops
off

Manual
transmission

60
to
70

rpm

Automatic
transmission

in
D

position

15
to
25

rpm

12

Connect
air
hose

to
air

check

valve

If

engine
speed
increases

readjust
it

to
the

specified

speed
with

throttle

adjusting
screw

Idle
limiter

cep

Do
not

remove
this
idle

limiter

cap

unless

necessary
If
this
unit
is
re

moved
it
must

be

readjusted
at
lime

of

installation
To

adjust
proceed
as

follows

I

After

adjusting
throttle

or
idle

speed

adjusting
screw
check

to
be
sure

that
the
amount

of
CO
contained
in

exhaust

gases
meets

the
established

standard

2

Install
idle
limiter

cap
in

position

making
sure
that
the

adjusting
screw

can
rotate
another
1
8

turn
in

the

CO

RICH
direction

Carbo
to

per

CO

rich

450
lIS
rotation

t
CO
lean

J

SQ

dl
lim

ET031
1
e
Iter

cap

Fig
EF

36

Setting
idle
limiter

cap

FUEL

LEVEL

1

Turn

down
float

chamber
to
al

low
float
to

come
into

contact
with

needle

valve
and
measure

Hu
shown

EF
22
in

Figu
re
EF

37

When
H

is

approximalely
7

mill
0
283

in

lOp
float

position
is

correct

The

top
float

position
can

be
ad

justed
by

bending
float

seat

Upon
completion
of
the

adjust

ment

check
fuel
level
wi
th

attached

level

gauge

p

j

i

I

it

I
Float
seat

2

Float

3

Float
chamber

4
Needle
valve
t
I
IIf

ET032

Fig
EF
37

Adjusting
float
level

2

Adjust
bottom
float

position
so

that
clearance
h
between

float
seat

and
needle

valve
stemis
I

3
to
L
7

mm

0
051
to
0
067
in
when

Iloat
is

fully

rals
n

Jloa
t

goppe

q
re

3

After

adjustments
in

steps
I
and

2

above
have
been
made

make
sure

that

when
fuel
is

delivered
to
the
float

chamber

the
fuel
level
is
maintained

within
the

range
of23
mm

0
91
in

as

shown
in

FigureEF
38

H
23

mm
0
91
in

EF260

Fig
EF
38

Checking
ruellevel

FAST
IDLE

I
With

carburetor

assembly
reo

moved
from

engine
measure
throttle

valve

clearance
A

with
a

wire

gauge

placing
the

upper
side

of
fast

idling

screw
on
the
first

step
on
fast

idling

cam

EC527

Fig
EF
39
Mea

uring
throttle
valve

clearance

MfT

AfT

3
To

check
fast

idling
cam

setting

by
engine

speed
proceed
as
follows

Warm

up
engine
sufficiently
Set
Engine
Fuel

Fast

idling
earn

steps

o

04th

l

2nd

1st

EC528

Fig
EF
40
Fast

idling
cam

steps

2
The
clearance
should
be

specified

value
in

the

following
table
If
not
ad

just
the
clearance

by
turning
fast

idling
screw

Clearance
A
mm
in

1
33
to
I

47
0

0524
to
0

0579

1
58
to
1

72
0

0622
to
0

0677

fast

idling
cam
at
2nd

step
and
read

engine

speed
Fast

idling
cam
is

prop

erly
set
if

engine
speed
is
within

Engine
speed

rpm
Fast

idling
earn

MfT

AfT

VACUUM
BREAK

I

Close
choke
valve

completely

2
Hold
choke
valve

by
stretching
a

rubber
band
between
choke

piston

lever
and

stationary
part
of
carburetor

3

Grip
vacuum
break
rod
with

pliers
and

pull
straight
out

4
Under
this
condition

adjust
the

clearance
between
choke
valve
and

carburetor
body
B
in

Figure

EF
42
to

specified
value

by
bending

vacuum
brake
rod
I
900
to
2
800

2nd

step

2
200

to
3
200

S
B

j
CK
iXo

LL

r
I

il

L
J

1

Choke

piston
rod

2

Choke

spring

3
Choke

piston
EF516

4

Diaphragm
cover

5
Choke

piston
lever

6
Choke
valve

Fig
EF
42

Adjusting
vacuum
break

EF
23
Z

ET033
Fast

idling
carn

Nut

Fast

idling
screw

Choke
valve

Choke

connecting

rod

Throttle
valve

Fig
EF
41

Adjusting
the
clearance

of
throttle
valve

Fast

idling
earn

1st

step

specifications
below
Clearance
A
in

2nd

step
is

reference
value

Clearance
A

mm
in

0
94
to
1
18
0
0370
to
0
0465

L16
to
I
40
0
0457

to
0
0551

CHOKE
UNLOADER

Close
choke
valve

completely

2
Hold
choke
valve

by
stretching
a

rubber
band
between
choke

piston

lever
and

stationary
part
of
carburetor

3
Pull
throttle
lever
until
full

open

Under
this
condition

adjust
clear

ance
between
choke
valve
and
carbure

tor

body
to

2
45
mm
0
096
in

by

bending
unloader

tongue

Note
Make
sure
that
throttle
valve

opens
when
carburetor
is
mounted

on
the
vehicle

If
throttle
valve
rails
to

open
un

loader
becomes

inoperative
resulr

ing
in

poor
acceleration
after

engine

is
started

ELECTRIC
AUTOMATIC

CHOKE

Checklna
automatic
choke

heater
circuit
with
function

test
connector

Caution
Do
not
altach
test

leads
of

a

circuit
tester
to
those
other
than

designated
Refer
to

figure
Ef
43

I

With

engine
not
running
check

for

continuity
between
A

and
B

as

shown
in

figure
Ef
43

If

continuity
exists
heater
is
func

tioning
properly

If

continuity
d
s

not
exist
check

for
disconnected
connector

or

open

P
T

e
heater
circuit

2

With

engine
running
at
idle
check

for

presence
of

voltage
across
A
and
B

as
shown
in

figure
EF
43

If

voltmeter

reading
is
12
volts

d
c

heater
circuit
is

functioning

properly

If

vohmeter
reading
is
zero
check

for
disconnected
connector
open

circuit
or

faulty
automatic
choke

relay

3

Replace
faulty
parts

J
j

N

j

EF710
1

ignition
key

2
Automatic
choke

relay

Engine
stop
OFF

Engine
start
ON

3
Automatic

choke
heateI

4

Function
test
connector

5
Altema
tor

Fig
EF
43
Checking
oulomalic

choke
heater
circuit
with

fu
nc
non
led

connector
Engine
Fuel

Automatic
choke

I
Before

starting
engine
fully
de

press
al
celerator

pedaJ
to
ensure
that

choke
valve

doses

properly

Push

choke
valve
with
a

finger

and
heck
for

binding

3
Check
0
be
sure
that
bi

rnetal

cover
index

mark
is
set
at
the
cen
leT
of

choke

housing
index
mark
a
s
shown
in

Figure
EF
44

Note
Do
not
set
b
metal
cover
index

mark
at

any
position
except
the

center
of
choke

housing
index

marl

tE

jL

J

Thermostat
cover

Bi
metal

chamber

2
Thermostat

housing

3
Groove
ET034

Fig
EF

44
Bi

metol
tting

4

Check
automatic
choke
heater

source

wiring
for

proper
connection

then
start

engine

5

After

warming
up
the

engine
see

that

choke
valve
is

fully

open

6
If
automatic
choke
heater

source

wiring
is

normal
and
choke

valve
does

not

operate
after
warm

up
replace

hi

metal
co
t
er

Automatic

choke

relay

I
Remove
automatic
choke

relay

Auto
choke
heater

relay

EF278

Fig
EF
45
Location

of
automatic

choke

relay

EF
24
2

Make
an

operational
check
of

automatic
choke

relay
as
shown
in

Figure
EF
46

Apply
2

volts
d
c
across
termi

nals
I
and
3
to
ensure
that

i

ontinuity
exists
between
terminals

2
and
4

Check
t
lal

continuity
does
not

exist
between
terminals

2
and
4

when
no

voltage
is

applied
across

them
If
results
satisfies
the
above

automatic
choke

relay
is

functioning

properly
if
not

replace
choke

relay

1
2

3

y
4

EF723

Fig
EF
46

Checking
automatic
choke

relay

Automatic
choke
heater

I
Measure
resistance
of
choke

heater

as
shown
in

figure
EF
47

spe
ified
re
s

an
ce
is
3
7
to
8
9

ohms

F

EF261

Fig
EF
47
Automatic
choke
heater

check

2
If
measured
value
is

not
within

the

specification
replace
bi
metal

cover

INTERLOCK
OPENING
OF

PRIMARY
AND
SECONDARY

THROTnE
VALVE

Figure
EF
48
shows

primary
throt

tie
valve

opened
SO
When

primary

throtlle
valve
is

opened
50
the

adjust

plate
integrated
with
throttle
valve
is

in
contact
with
return

plate
at
A

When
throttle
valve
is

opened
fur

ther

locking
arm
is
detached
from

secondary
throttle
arm

permitting
see

ondary

system
to

start

operation

Linkage
between

primary
and

see

ondary
throttles
will
function

properly

if
distance

between
throttle
valve
and

inner
wall

of
throttle

chamber
is
74

mm

0
291
in

Adjustment
is
made

by
bending

connecting
link

I

L
l

1

4
CAl

Secondary
prm

ary
I

Jl
I

7
t
@

1
Roller

4

Adjust
plate

2

Connecting
lever

5
Throttle
c
amber

3
Return

plate
6
Throttle
valve

Fig
EF

48

Adjusting
interlock

opening

DASH
POT

1

Idling
speed
of

engine
and
mix

ture
must
be

well
tuned

up
and

engine
sufficiently
warm

2

Turn
throttle
valve

by
hand
and

read

engine
speed
when

dash

pot

just

touches

stopper
lever

3

Adjust
position
of

dash

pot
by

turning
nut

until

engine
speed
is
in
the

specified
range

Specified
engine

speed

Manual
transmission

1

900
to
2

100

rpm

Automatic
transmission

1
650
to
1

850

rpm

4

Tighten
lock

nuts

5
Make

sure
that

engine
speed

drops
smoothly
from
2

000
to
1

000

rpm
in

about
three

seconds
Engine
Fuel

Fig
EF
49

Adjusting
dash

pot

ACCELERATING
PUMP

I

Visually
inspect
accelerating

pump
cover
for

any
sign
of
fuel
leaks

2
If

fuel
leaks
are
found
check

gasket
and

replace
if

necessary

ANTI

DIESELING

SOLENOID
VALVE

If

engine
does
not

stop
when

igni

tion
switch
is
turned
off

this
indicates

that
a

striking
closed
solenoid

valve

is

shutting
off

supply
of
fuel
to

engine

If
harness
is
in

good
condition

replace
solencid
valve
as
a
unit

Notes

a

Tightening
torque
is
1

8
to
3
5

kg
m
13
to
25

ft
Ib

b

After

replacement
star

engine
and

check
to
be
sure
that
fuel
is
not

leaking
and
that
anti
dieseling

sol

noid
is
in

good
condition
B
C
D
D

CIRCUIT
WITH

FUNCTION
TEST

CONNECTOR

Caution
Do

not
attach
test
leads

of
a

circuit

tester
to
those
other

than

designated
Refer
to

Figure
EF

50

Menuel

trensmlsslon
models

I

Check
for

continuity
between
A

and
B
when

vehicle
is

brought
to
a

complete
stop
Refer
to

Figure
EF

50

B
C
D

D
circuit
is

functioning

properly
if

continuity
exists

and
volt

meter

reading
is

0
volt

d

c
in

step
2

below

If

continuity
does
not
exist

check

for

disconnected
connector
and
or

faulty
amplifier
speed
detecting

switch

or
B
C
D
D
solenoid
valve

2

Check
for

presence
of

voltage

across
A

and
B
at

a

speed
of
more

than
16

km
h

10
MPH
Refer
to

Figure
EF

50

Conduct
this

test

by
one
of
the

following
two

methods

I
Raising
up
rear
axle

housing
with

stand

2
Chassis

dynamometer
test

If
voltmeter

reading
is
0

volt
at
a

speed
of
more
than
16
km
h
10

MPH
circuit
is

functioning
prop

erly

If
voltmeter

reading
is
not
0
volt

check
for
disconnected
connector

burned
fuse

faulty
amplifier

B
C
D
D
solenoid
valve
or

speed

detecting
switch

3
If

by
above
checks

faulty
part
or

unit
is
located
it
should
be

removed

and
tested

again
If

necessary
replace

1

P4
11
0

8

l
1

Ignition
Icey

2

Fuse

3

Amplifier

4

Speed
detecting
switch

Above
10

mph
OFF

Below
10

mph
ON

5

Function
test
connector

6
B

C
D
D

solenoid
valve

EF711

Fig
EF

50

Checking
B
C
D
D
circuit
with

function
test

connector

for
manual
transmission

EF
25