1973 DATSUN B110 fuel pump

ENGINE

FUEL
PUMP

TESTING

A
fuel

pump
is

operating
properly
when
its

pressure
is

within

specifications
and
its

capacity
is

equal
to
the

engine
5

requirements
at
all

speeds
Pressure
and

cap
lcity
must
be

determined

by
two
tests

with

the

pump
mounted
on
the

engine
Be

sure
that

there

is

gasoline
in
the

tank
when

conducting
these

tests

Fig
EF
11
Schematic
view

of
fuel
pump

Static

pressure
test

The

static

pressure
test
is

conducted
as
follows

Disconnect
the
carburetor
fuel
line
at

the
carburetor

2
Install
the

necessary
adapter
and
tee

fitting
to
the

fuel
line

and
attach
a

suitable

pressure
gauge

Start
and
run

engine
at

varying
speeds

4

The

reading
on
the

gauge
is
the

static
fuel

pressure

and
this
should
remain
within
the

following
limits

0
18

kgJcm2
2

61b

sq
in

Pressure
below
the
lower
limit

indicates
extreme
wear

on
one

part
or
a
small
amount
of
wear

on
each

working

part

They
also
indicate
a

ruptured
diaphragm
worn

warped
dirty
or

gumming
valves

and
seats
or
weak
diaphragm
return

spring
Pressure
above
the

upper
limit

indicates
an

excessively
strong

diaphragm
that
is

too

tight

This
condition

requires
removal

of
the
fuel

pump
as

sembly
for

replacement
or

repair

Capacity
test

The

capacity
test

is
used

only
when
the
static

pressure

is
within

specifications
The

capacity
test
is
conducted
as

follows

1
Disconnect
the

fuel

pipe
at

the
carburetor

2

Place
a
suitable
container
at

the
end

of
the

pipe

3

Start
the

engine
and
run
at
1

000

rpm

4

The

pump
should
deliver
450
cc
I
V
S

p
of
fuel
in

one
minute

or
less

EF
6

FUEL
SYSTEM

If
no

gasoline
or

only
a
little
flows
from

open
end

of

pipe
the
fuel

pipe
is

clogged
or
the

pump
is
malfunction

ing
Before

removing
the

pump
remove
the

gas
tank

cap

disconnect
both
inlet
and
outlet

pipes
and
blow

through

them
with
an
air
hose

to
make
sure
that

they
are
clear

This
will
eliminate

possible
clogged
gas
strainer
in
the

fuel
tank
Reconnect
the

pipes
to
the

pump
and

retest

flow

REMOVAL
AND
DISASSEMBLY

Remove

the
fuel

pump
assembly
by
unscrewing
two

mounting
nuts
and
disassemble
in
the

following
order

1

Separate
the

upper
body
and
the

lower

body
by

unscrewing
the

body
set
screws

2
Take

off
the

cap
and
the

cap
gasket
by
removing
the

cap
screw

3
Unscrew

the
elbow
and
the

connector

4
Take

off
the
valve
retainer

by
unscrewing
two

valve

retainer

screws
Two

valves
are

easily
removed

@

@

GS
5
To
remove
the

diaphragm
diaphragm
spring
lower

body
seal
washer

and
lower

body
seal
from
the

lower

body
press
down

the

diaphragm
counter
to

the
force
of

the

diaphragm

spring
and
while

doing
this
cant
the

diaphragm
so
that
the

rectangular

part
in
the

lower
end
of

the

pull
rod
is

unhooked
from
the
rocker

arm
link

Fig
EF
jJ
StructuTe

of
fuel
pump

EF
7
j

i

I
of

4

Fig
EF
12
Pull
Tad
Temoval

r1
r

f
i

t

1

2

3

4

5

6

7

B

9

10

tt

t2

t3

t4

15

t6

t7

tB

t9

20

2t

22

23

24
Valve
assem

bly

Packing

Retainer

Screw

Cap

Gasket

Screw

Washer

spring

Rocker
arm

Rocker

pin

Rocker
arm

spring

Spacer

Diaphragm
assembly

Retainer

Diaphragm
spring

Washer

spring

Nut

Washer

plain

Gasket

Spacer

Complete
body
lower

Connector
inlet

Connector
outlet

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

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

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

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