1968 DATSUN 510 Service Repair Manual

68
CHAPTER
SEVEN

Capacity
Test

Perform
the

capacity
test

only
when
the
statIc

pressiue
test
IS
withm

acceptable
lirmts

1

D
sconnect
the
fuellme

at
the
carburetor

2
Place
a
sUItable
container
at

the
end
of
the

fuellme

3

St
lrt
the

engm
and

run
at
OOO

rpm

4
The
fuel

pump
should
delIver
fuel
into
the

co
ntainer
at
a
rate

slightly
over
two

pints
per

minute

If

no

gasolme
or

only
a
lIttle

appears
the
fuel

lme
is

clogged
or
thefuel

pump
defectIve
Bef

removmg
the
fuel

pump
remove
the

gas
tank

filler

cap
dtsconnect
the
mlet
and

outlet
fuel

lmes
and

qlow
through
them
With

compressed

air
to
make
certam

they
are
clear
Reconnect
the

fuellmes
and
retest
the
flow
If
stIll

insufficient

the
fuel

p
mp
requires
servicmg
or

replacement

Fuel

Punip
Removal
and

Disassembly

1
Unscrew
the

two

mountIng
nuts

hOldmg
fuel

pump
to
the

cylmder
head

2
Disconnect
the
inlet
and
outlet
lines

3
Remove
the
fuel

pump
from
the

cylmder

head

4
Place
the

pump
on
a
work
bench
and
remove

the
screws

jommg
the

upper
and
lower

bodIes

5
Remove
the

cap
and

gasket
by
removing
the

cap
screws

6
Unscrew
the
elbow
and
connector

7
Remove
the
valve
retamer

by
unscrewmg
the

two
valve
retamer
screws
The
two
valves
are

then

easily
removed

8
To
remove
the

dIaphragm
spring
lower

body

seal
washer
and
lower

body
seal
from
the
lower

body
press
the

diaphragm
down
Wh1le

domg

thIS
cant
the

dIaphragm
so
that
the

rectangular

part
m
the
lower
end
of
the

pull
rod

unhooks

from
the
rocker

arm
lmk
ThIS
action
IS
shown

mFigure7

9
Drive
out
the
rocker
arm

pm
by
usmg
a
dnve

dnft
nd
hammer

Fuel

Pump
Inspection

1

Check
the

upper
and
lower
bodIes
for

cracks

2

Check
the
valve

assembly
for
wear
on
valves

and

springs
CD

3
Check
the

diaphragm
for
small
holes
cracks

and
wear

4
Check
the
rocker
arm
for
wear
where
It
con

tacts
the
camshaft

5
Check
the
rocker
arm

pin
for

wear
A
worn

pin
may
cause
011

leakage

6
Check
all
other

parts
for
abnormalItIes
or

defects

Replace
With
new

parts
as

reqUlred

Reparr
kIts
are
available
from
Datsun
dealers

and

parts
outlets

Fuel

Pump
Assembly

1

Assembly
of
the
fuel

pump
is
the
reverse
of

dlsassembly

2
Use
new

gaskets
durmg
assembly
and

mstanatIon

3
Lubncate
the
rocker
arm
the
rocker
arm

link
the
rocker
arm

pm
and
the
lever

pin
before

mstallatIon

4
To
test
the

operatIon
ohhe
fuel

pump
before

remstallatlOn
connect
a
three
foot

pIece
of
fuel

lme
or
hose
betweentbe
fuel
filter
and
the
fuel

pump
Hold
the
fuel

pump
at
the
end
of
the
fuel

lme

conSIderably
above
the
level
of
the
fuel

stramer

Operate
the
rocker
arm

by
hand
If
fuel

IS
drawn

up
to
the

pump
soon
after
the

pumpmg

actIon
IS
started
the

pump
IS

satIsfactory

5
Install
the
fuel

pump
to
the

cylmder
head
and

secure
the

mounting
nuts
to

the
studs

6
Reconnect
the
mlet
and
outlet
fuellmes

7
Check
the

operatIon
of
the
fuel

pump
by

runnmg
pressure
capaCIty
tests
as
descnbed

preVIously

FUEL
SYSTEM
69

CARBURETOR

The
carburetor
IS
an
Hltach1

Type
DAF328

Several
varIations
are
used

dependmg
on
the

model

year

type
of
transmissIOn
and
the
emIS

SIon
control

system
The
dIfferent
models
are

the
same
as
far
as
basiC

operation
IS
concerned

Therefore
the

followmg
dISCUSSIon
covers
a

typIcal
carburetor
The

automatIc
choke
IS
used

on
automatIc
transmISSIon
and
1972
models

only
All
other
chokes
are
manual

Refer
to

Figure
8
The
carburetor
conSIsts
of

a

pnmary
system
used
m
normal

runnmg
and
a

secondary
system
used
for

hIgh
speed
or

heavy

load

operatIons

CARBURETOR
ADJUSTMENT

Idling
Adjustment

Idle

adjustment
IS
made

by
the
throttle

adjust

and
Idle

adjust
screws
both
of
wh1ch
are
located

at
the
bottom
of
the
carburetor

1

Screw
the
Idle

adjust
screw
all
the

way
in

to

the

fully
closed

pOSItIon
Do
not
over

tIghten

CD

6
2
Unscrew
the
Idle

adjust
screw

approXImately

three

cor
nplete
turns

3
Screw
m
the
throttle

adjust
screw
two
or
three

turns
and
start
the

engui
e

4
Screw
out
the
throttle

adjust
screw

slowly

until
the
onset

roughness
followmg
a

gradu81

speed
drops

5
Screw
m

the
Idle

aOJust
screw
untIl
the

engme

runs

smoothly
at
the

hIghest

speed

6

Readjust
the
throttle
screw
to

drop
the

engme

speed
Repeat
these

adjustments
untIl
a
smooth

engme
speed
at
the

proper
Idle

rpm
IS
ach1eved

Refer
to
the
tune

up
chapter
for

proper
rpm

Fuel
Level

Adjustment

Constant
fuel
level
IS
mamtamed

by
the
float

and
the
needle
valve

Figure
9
sb
ws
the
fuel

level

system
wlthm
the
carburetor
If
the
level
IS

at
the
lIne
on
the

f
lel
reservOir
level
is

properly

set
If
not

adjust
It

by
bendmg
the
float
seat

Adjust
the

gap
between
the
valve
stem
and
the

float
seat
to
00591
m

1
5mm
with
the
float

fully
luted

up
by
bendmg
the
float

stopper

1213141516

20

I

h

r

1
Secondary
main

nozzle

2
Secondary
small
venturi
10

Secondary
bypass
hole
18

Primary
slow
air
bleed

3

Secondary
main
air
bleed
11

Secondary
throttle
valve
19
Air
vent

4

Secondary
slow

Jet
12
Choke
valve
20
Level

gauge

5

Secondary
slow
air
bleed
13

Primary
main
air
bleed
21

Primary
main

Jet

6
Needle
valve
14

Primary
main
nozzle
22
Idle
limit
screw

7
Float
15
Economizer
bleed
23
Idle
hole

8

Secondary
emulSion
tube
16

Primary
slow

let
24

Bypass
hole

9

Secondary
main

Jet
17

Primary
economizer
25

Primary
throttle
valve

70

CHAPTER

SEVEN

CD
1
Float
seat

2
Roat
3

Roat

stopper

4
Needle

valve

Starting
Interlock
Valve

Opening
Adjustment

Figure
10
shows

the
Interlock
valve

openmg

mechanISm
The
choke

valve
at
a
full

closed

pOSItion

automatIcally
opens
the

throttle
valve

at

a
16

degree

angle
for

startlng
ter
reassem

bly
or
to
set
the
interlock

opening

angle
bend

the

choke

connectlng
rod

so
that

a

fully
closed

choke

valve
will
leave

a
clearance

of
0
0512
m

1
3mm
between
the

choke
valve
and
the
throt

tle
chamber
ThIS

IS
shown

as
dImension
A
in

Figure
10

@

7

1
Crank

rod
6
Choke

connecting
lever

2
Choke

crank
le
er
7
Throttle
lever

3

Choke
lever
8
Throttle
chamber

4
Choke
VBI
e
9
Throttle
lever

5
Choke

connecting
rod
Interlock

Opening
of

Primary
and

Secondary
Throttle
Valves

Refer
to

Figure
11
The

primary
throttle

valve

should
be
at
a

degrees
When
the

adjust

plate

I

fixed
to
the

pnmary
throttle

valve
IS

open
to
a

degrees
It
comes
In
contact

WIth
the

connecting

lever
at

pOInt
A

When
the
throttle
valve
is

opened
further
where

the

connectIng
lever
IS
in

contact
With
the

stopper

POInt
B
the
connect

mg
lever
detaches

and
the

secondary
system
is

actllated
The

lInkage
between
the

pnmary
and

secondary
throttles

operates
properly
if
the
dis

tance

6etween

theilirotlle
valve
anainner
will

of
the
throttle
chamber
G
amounts

to
the
fol

lowmg
a

degrees
IS
59

degrees
DImenSIon
G

IS
03583
In
910mm

Figure
12
shows

the

measurement

bemg
checked

@

2

Secondary

I

1

Connecting
le
er

2
Return

plate

3

Adjusting

plate
4
Throttle

chamber

5
Throttle
valve

I

1

I

r

t
i
t
r

1
I

j

I

00

I
r
@

FUEL
SYSTEM
71

Dash
Pot

Adjustment

The

adjustment
of
the
dash

pot
IS
done

by

warmmg
up
the

engme
properly
and

checkIng
If

the
throttle
lever
touches
th
dash

pot
stem
as

the

engine
reaches
1
800
and
2
000

rpm
under

no
load
conditIons

Proper
contact
between
the

throttle
lever
and
the
dash

pot
stem

produces
a

normal
dash

pot
performance
Should
a
normal

mcrease
m

engme
speed
not
occur

adjust
the

dash

pot
as
follows

1
Loosen
the
dash

pot
locknuts

2
Rotate
the
dash

pot
nght
and
then
left

3

Adjust
the
dash

pot
so
that
the
throttle
lever

hIts
the
stem
between
1
800
and
2
000

rpm

4
Fasten
the
lock
nuts

securely

5
The
clearance
between
the
throttle
valve
and

the
throttle
chamber
wall
should
be
0
0709
m

0
8mm

or
10

degrees
In
throttle
valve

angle

MAJOR
CARBURETOR

SERVICE
PROCEDURES

A
carburetor
m

good
operatIng
condition
will

delIver
the

pr
per
gasolme
and
aIr
ratIos
for
all

engme
runnmg
speeds
A

gradual
declme
In

smoothness

response
and

power
Will
occur
as

the
carburetor

slIps
from

adjustment
and
Its
delI

cate

parts
become

dirty
and
worn
Overhaul

should

only
be

attempted
by
an

expenenced

mechanic

Accurate
calIbratIon
of

passages
and
dIS

charge
hole

reqUIre
that

extreme
care
be
taken

In

dISassembly
cleanmg
and

reassembly
Use

only
a

hIgh
grade
carburetor
cleaner
and
com

pressed
arr
to
clean

parts
and

passages
Never

use
wire
or
other

pOInted
Instruments
for
clean

ing
CalIbratIon
of
the
carburetor
will
be
af

fected
The

procedures
below
are

generally
true

for
all
models
As
an
aId

Figures
13
and
14
are

typIcal
examples
of
the
carburetors
used

Carburetor
Removal

1
Remove
the
au
cleaner

by
dIsconnectIng
all

hoses
attached
to
It

remoVmg
the
two
bolts

holdmg
the

aIr
cleaner
to
the

support
and

loos

enmg
the
band
bolt
at
the
base
of
the
aIr
cleaner

2
DIsconnect
fuellme
vacuum
Ime
and
choke

wire
u

eqUIpped
from
the
carburetor
3
Remove
the
throttle
lever

4
Remove
four
nuts
and
washers

holdmg
car

buretor
to
manIfold

5
Lift
carburetor
off
of
manuold

6
Remove
and
dIscard
carburetor
to
manuold

gasket

7
Place
carburetor
on
clean
workbench

Carburetor

Disassembly

1
The
maIn

Jets
slow

Jets
and
needle
valves
on

both
the

pnmary
and

secondary
systenIS
are

accessIble
from
outsIde
the
carburetor
Refer
to

FIgures
13
and
14
for
locatI
n

2
The
choke
chamber
can
be
detached

by
re

mOVIng
the

connectIng
rod

pump
connectIng

rod
return

sprmg
stop
pm
and
the

set
screws

I

that
hold

It
in

place

3
The

pnmary
and

secondary
emulSIon
tubes

can
be
disassembled

by
remOVIng
the
mam
air

bleeds

on
the

respectIve
SIdes

4

To
check
the
accelerator

pump
remove
the

cylInder
cover
Be
careful
not
to
lose
the

return

spnng
and
Inlet
valve
at
the
lower

part
of
the

pIston
durmg
dIsassembly

5
Detach
the
throttle
chamber
from
the
float

chamber

by
remOVIng
the
rod

lInkIng
the
dia

phragm
WIth
the

secondary
throttle
valve
and

the
four
screws
that
hold
It
However
It
IS

preferable
to
leave
the
throttle
valve
mtact
unless

absolutely
reqUired
If

It
IS

necessary
to
dlS

assemble
the
valve
It
should
be
Installed
so
that

the

secondary
throttle
valve
will
be

gap
free

OtherwIse
stable
Idle
and

good
slow

speed

performance
will
suffer

is
To
check
the
float
the
float
chamber
cover

must
be
removed

I

7
The

dIaphragm
IS
dIsassembled

by
removing

the
set
screws

holdmg
the

dIaphragm
chamber

cover
In

reassemblIng
the

diaphragm
be
careful

not
to
turn
the

edge
of
the

dIaphragm
up

8
In

dlsassemblmg
and

reassembling
the
mter

lockIng
lInks
take
care
so
that
each

lInkage
has

a
smooth
actIon
and
that

parts
are
not
forced

mto

pOSItIon

9
For
vehIcles

equipped
With
an
automatIc

choke
remove
the
brmetal

case

by
releasmg
the

set
screws
The
bimetal

1l
extremely
senSItIve

a

C1
1AyTEll
Sy
VEN

@

t

i

o

j

J

1
I

cP
C
O
c
o
I

I

4
J

j

2
Primary
throttle
shaft
45
Float
cover
gasket
82
Screw
I
f
l

3
Secondary
throttle
shaft
46
Float
cover
84
Spring
washer

4
Primary
throttle
valve
47
Float
cover
gasket
86
Screw

5
Secondary
throttle
valve
48
Float
cover
holder
88
Spring
washer

6
Screw
49
Screw
89
Stopper
pin

7
Throttle
adJust
lever
51
Sprln
g
washer
90
Slow
Jet

8
Washer
53
Needle
valve
assembly
91
Slow
Jet

9
Return
plate
54
Washer
92
Slow
air
bleed

10
Sleeve
55
Filter
94
Screw

11
Connecting
lever
56
Fuel
va
por
discharge
95
Screw

12
Throttle
lever
con
nectar
98
Screw

13
Throttle
lever
57
Washer
99
Spring
washer

14
Nut
58
Filter
set
sc
100
Spring
washer

15
Spring
washer
59
Fuel
return
clamp
101
Choke
shaft

16
Throttle
adJust
screw
60
Screw
102
Choke
valve

17
Throttle
adJUst
spring
61
Plain
washer
104
Choke
lever
spong

18
Idle
adJust
screw
62
Washer
105
Choke
lever

19
AdJust
screw
spring
64
Ball
106
Choke
valve
spring

20
Throttle
camber
gasket
65
Piston
return
spring
107
Choke
connecting
rod

21
Screw
66
Pump
inJector
spring
108
Rod
pump
spnng

22
Screw
67
Piston
109
Rod
choke
washer

23
Spring
washer
68
Pump
cover
110
Pump
lever

24
Venturi
gasket
69
Cylinder
plate
112
Ring

25
Screw
70
Screw
113
Pump
rod

27
Spring
washer
71
Spring
washer
114
Choke
wire
holder

28
Main
air
bleed
72
Ball
assembly

29
Main
aIr
bleed
73
Pump
Injector
115
Screw

30
Secondary
emulsion
tube
74
Washer
116
Screw

31
Primary
main
jet
75
Injector
set
crew
117
Spring
washer

32
40
Secondary
R
1aln
jet
76
Diaphragm
assembly
118
Crank
rod

41
Drain
plug
77
Diaphragm
spring
120
Throttle
return
spring

42
Packing
79
Ball
121
Dash
pot
assembly

43
Float
assembly
80
Valve
spring
122
Nut

44
Collar
81
Diaphragm
cover
I
I
4

6

@

FUEL
SYSTEM
75

s

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1
11
1
I
1
1
l
l
l
l
l
l
lC

lC
lC
l
and
delIcate
Therefore
do
not

attempt
to
force

It

Improper
handlmg
WIll
cau
e
dIstortIOn

10
In

assemblIng
the
bImetal

place
the
ther

mostat

cover

gaSket
gently
In

place
and
mstall

the
thermostat
cover
after

makmg
sure
that
the

lever
on
which
the
bImetal

hangs
moves

smoothly

11
After

ughtenmg
completely
bend
and
ad

Just
the
bImetal
rod
so
that
the

upSIde
of
the

bImetal
case
IS
level
withm
0
02
m
O
5mm
of

the
slIt
on
the
bImetal
rod
Be
sure
the
bImetal

rod

operates
smoothly

12

Adjust
the
choke
valve

opening
to
00709

m

1
8mm

by
bendIng
the

connecting
rod

Carburetor

Cleaning
and

Inpection

Dirt

gum
water
or
carbon
contammation
of

cntIcal

parts
IS
often

responsIble
for
unsatlsfac

tory
carburetor

performance
Careful

cleanmg

and

InspectIon
IS
therefore
essential

1
After

disassembly
submerge
all

parts
In
a

specIal
carburetor
cleaner
Be
certam
to
follow

the
mmufacrurer
s
instructions
In

usmg
the

cleaner

2
After

cleanmg
blow
all

passages
and
cast

mgs
With

compressed
aIr
Make
certam
all

parts

are

completely
dry

3

Carefully
mspect
parts
for

SIgnS
of
wear

VISIble
wear
IS
suffiCIent
cause
to

replace
a

part

4

Pay
speCIal
attentIon
to
condItIon
of
the
float

seat
and
needle
the
throttle
and
choke
shaft

bores
In
the
throttle

body
and
cover

castIngs
and

to
the
Idle

adjustIng
needles

5

Inspect
all

gaskets
to
see
IT

they
are
hard

or

bnttle
or
IT
the

edges
are
tom
or
dIstorted
It

IS

sound

practIce
to

replace
them
whenever
the

carburetor
is
dIsassembled

6
Check
the
filter
screen
for
dIrt
or
lint
If
after

cleanmg
It
IS
not

completely
clean

replace
It

7
Check
all

lInkages
for
smooth

operatIon

Correct
as

reqUIred

8
Check

operation
of
the
acceleration

pump
by

puttIng
gas
m
the
float
chamber
and

operatIng

the
throttle
lever

by
hand
Fuel
should
be

pumped
from
the

acceleration
nozzle
IT
the
unIt

IS

satlsfactory

9

Carefully
InSpect
the

dIaphragm
for
holes
or

leaks

Replace
IT
defective
il