1969 DATSUN B110 engine

Fuel

Sptem

Testing

A
fuel

pump
IS

operatIng
properly
when

1tS

pressure
IS
Within

specifications
and
ItS

capacIty
IS

equal
to

the

engine
s

reqUIrements

at
all

speeds

Pressure
and

capacity
must

be
determined

by

two
tests
With
the

pump
mounted
on
the

engIne
Be

sure
that

there
IS

gasohne
m

the

tank

when

conductIng
these

tests

Fig
89
Pull

rod
removal
StatIc

Pressure
Test

The
static

pressure
test
IS
conducted

as

follows

Disconnect
the
carburetor

fuel
line
at
the

car

buretor

Install
the

necessary

adapter
and
tee

fitting

to
the
fuel
Ime
and
attach

a
SUitable

pressure

gauge

Start

and
run

engme
at

varymg
speeds

The

readIng
on
the

gauge
IS

the
static

fuel

pressure
and

thIS

should
remam
wlthm

the

follOWing
Itmlts

2
61b

sq
m

Pressure

below
the
lower
hmlt

IndlCates
ex

treme

wear
on

one

part
of
a
small
amount

of

wear
on
each

working

part

They
also
md1cate
a

ruptured
dIaphragm

worn

warped
dirty
or

gummmg
valves
and

seats

or
weak

dIaphragm
return

spring

Pressure
above

the

upper
hmlt

Indicates
an

excessIVely
strong
dIaphragm
that

IS
too

tight

ThIS

condItIOn

reqUIres
removal
of
the

fuel

pump

assembly
for

replacement
or

repair

I

V
lvc
llllh

2

PdlklOg

3
Retamer

4

Stre

5

p

6

Ga
ket

7
Screw

8
Washer

prln

9
Rocker
Jrm

10
Rocker

pm

II

Ro
ker
fm

pTln

12

Spdcer

13

Diaphragm
assembly

14

15
Retiuner

16

Diaphragm
sprtng

17
Washer

5PIlllg

18
Nul

19
Washer

plalO

20
Ga
ket

21

Spacer

22

Complete
body
lower

23
Connector
anlet

24
Connector
outlet

Fig
90
Structure

of
fuel

pump

51

Fuel

Sptem

The

power
valve
mechanIsm

IS
of
a
vacuum

actuated
boost

type
and

Improves
hIgh
speed

drivIng

The
throttle

opener
control

system
Incor

porates
a
servo

diaphragm
The

servo

dIaphragm
helps
open
the
throttle
valve
at
a

decreasIng
speed
so
as
to
reduce
the
emISSIOn

of

hydrocarbons
to
a
minImum

An
antI

dlesehng
olen01d
IS
used
as

a
means

of

preventIng
dlesehng
When
the

IgnItIOn

key
IS
turned
ofT
the
fuel

passage
Involved
In

the
slow

system
IS
closed
and
the
fuel

supply

IS
shut
down

completely

In
the
chok
mechanIsm
an
electric

automatIc
choke
IS
used
to

automatically
con

trol
the
choke
valve

operatIOn
durIng
the

war

m

up
of
the

engIne

The
carburetor
for
automatic
transmiSSIOn
IS

eqUIpped
WIth
so
called
dash

pot
that
IS
It

makes
smooth

deceleratIng
WIthout

engIne

stall
at

any
operatIng
conditIOn

These
carburetors

are

qUIte
SImIlar
In

ap

pearance
as

explaIned
above

except
the
dash

pot
for
the
automatIc
transmISSion
model

Adjustment

Idhng
Adjustment

Idle
mixture

adjustment
requIres
the
use

of
a

CO
meter
When

prepatlng
to

adjust
Idle
mIxture
It
IS
essentIal
to
have
the
meter

thoroughly
warmed
and
cahbrated

Warm

up
the

engIne
suffiCiently

ContInue

engme
operatIOn
for

one
mmute
un

der

ldhng
speed

Adjust
throttle

adjustIng
screw
so
that

engme

speed
IS
800

rpm
m
N

pos1tIon
for

automatic
transmiSSIOn

Check

IgmtlOn
tl
If

necessary

adjust
It
to
the

speCificatIOns

IgnItIOn
tImlo
800
rpm

Adjust
Idle

adJustmg
screw
so
that
CO

percen

tage
IS
1

5
0
50
at
800
ns

a
On
automatIc

transmiSSIOn

eqUipped
model
check
must
be

done
In
the
D

poSItIon
Be
sure
to

apply

parkmg
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

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

for
Manual
transmISSion

for
Automatic
transmISSion

Fig
91
External
view
of
carburetor

3

Fuel

Sptem

ted

on
the
car
If
the
throttle
valve
fails
to

fully
open
the
unIoader
becomes

inoperative
resulting
in

poor
ac

celleration
after
the

engine
is

started
Note
Use
an
accurate

measuring
in

strument
such
as
a
wheatstone

bridge

B1
metal

cover

settmg

BL
metal

Settmg

Mea
urement
of
bl
metal
heater
resistance

Install
the
bl
metal

cover
m

place
on
the
car

buretor
Make
sure
that
the
resIstance
across

the
termmal
and
the
carburetor

body
IS
m
the

range
from

8
6
to
0
0
ohms
Measure
the

resIstance
without
electnc
current

through

the
heater
and
at
about
70
F
Postllon
the
bl
metal

cover
until
the
mdex

mark
1S

altgned
at
the
middle

pomt
of
the
scale

26
mm
I
024

m
dlJ

30
m
1
181
In
dlJ

Connectml
rod

Secondary
COnnCl

lms

lever

Throltle
lever
4

Secondary
throttle

vaJve

5
Pnmary
throttle
valve

6

Throttle
chamber

Fig
98
Settmg
bl
metal
cover

Fig
99
AdJustmg
mterlock

opening
Pnmary
and
secon

dary
throttle
valves

Fig
100

AdJustmg
dash

pot

17

ruel
S
stem

Note
When
somewhat
over
choked
set

bl
metal

cover
after

turning
it
clockwise

slightly

Adjustment
oflnterlock
Opelntng
of

Pnmary
and

Secondary
Throttle
Values

Open
the

pnmary
Side
throttle

valve
48
from

the

fully
closed

positIOn
and
measure

clearance
GIn
between
the
throttle
valve
and

throttle
chamber
mSlde
wall
as
shown
m

Figure
99

GIn

0
228
m

WIthout

dlsturbmg
the
above

settmg
bend

connectmg
rod
as

necessary
so
that

secoridary

throttle
valve
IS
about
to

open
Upon
com

pletIOn
of
the

adjustment
make

sure
that
the

hnk

system
operates
smoothly

Dash

Pot

Adjustment
AutomatIC
Trans

mlsszon
car

only

It
IS

necessary
that
the

Idhng
speed
of

engme

and

mIxture
have
been
well

turned
up
and

engme
IS
suffiC1
n

y
warm

1

Turn
throttle

valve

by
hand
and
read

engme

speed
when
the
da
h

pot
Just
touches
the

stop

per
lever

Adjust
the

pOSitIOn
of
the
dash

pot
by
turnmg

the
nut
until
the

engine

speed
IS
In

the

range

from
1

900
to
2
000

rpm

Make

sure
that
the

engine
speed
IS

smoothly

leduced
from

3
000
to
1
000

rpm
within
a
few

econds

Removal

Remove
the

aIr
cleaner

DIsconnect
the
fuel
line
vacuum
line

automatic
choke
harness
and
antl

dlesehng

solenOId
harness
from
carburetor

Remove
the
throttle
lever

Remove
four
nuts
and
washers

retaining
the

carburetor
to
the
mamfold
If

necessary

LIft
the
carburetor
and
remove
from
the

mamfold

Remove
and
dlscard
the

gasketcused
between

the
carburetor
and
mamfold

8
Disassembly

The
main

Jets
and
needle
valves
on
both

primary
and

secondary
Sides

are
accessible

from
outSIde
of
the
carburetor
for
disassem

bly
Remove
throttle
return

sprmg

Remove

pump
level
shaft
take
out

pump

lever
and

pump
connectmg
rod

Remove
rubber

pipe
from
choke

piston

Loosen
off
bolts

secutlng
servo

diaphragm
In

positIOn
take
out

dIaphragm

Back
off
total
of
five
bolts
which
hold
choke
In

posItion
and

remove
rods
of
starter

system

take
out
choke
chamber

In

removmg
chamber

exercise
care
to
aVOId

damaging
float

The

pnmary
and

secondary
emulsIOn
tubes

can
be
disassembled

by
removmg
the

main
air

bleeds

on
the
indiVidual
SIdes

UII
ij

Fig
101

Removmg
choke
chamber
and
servo

diaphragm

o

llQt

o

Fig
102
Removmg
emulsion
tubes

Fuel

SJstem

Check
float
needle
and
seat
for

wear

Replace

the

assembly
If

worn

Check
the
throttle
and
choke
bores
In
throttle

body
and

cover

castIng
for
wear
or
out

of
round

Inspect
Idle

adjustIng
needles
for
burrs

or

ndges
Replace
as

reqUIred

Inspect
gaskets
to

ensure
that

they
do
not

ap

pear
hard

or
bnttle
and
that
the

edges
are
not

turned

or
dIstorted
If

any
such
condItIOn
IS

detected

they
must
be

replaced

Check
filter
secreen
screen
for

cloggIng
Clean

and
If
It
IS
dIstorted
or
remaInS

plugged

replace

Check
cluster
for
loose

or
worn

parts
If

damage
or
Ioosene
s
eXists

replace
cluster

assembly

Check
the

hnkage
for

operatIng
condItion

Inspect
the

operatIOn
of

acceleratIng
pump

Pour

gasohne
Into
the
float
chamber
and

operate
the
throttle
hver
Check
conditIOn
of

gasohne
InjectIOn
from
the

acceleratIng
nozzle

Assembly
and
Installation

Assemble
and
Install
the
carburetor
In

I

everse

sequence
of

dIsassembly
and
removal
Replace
the

gaskets
If

necessary

When

dlsassembhng
and

reassembhng
the
In

terlock
hnk
and
related

components
be

careful
not
to

bend
or
deform
the

components

Reassembly
carefully
and

correctly
so
that
all

Interlock
hnks

operate
smoothly

Jets

The
carburetor

performance
depends
on

Jets

and

aIr
bleed
and
the
vehicle
emISSIOns

largely
depends
on
the
carburetor

performan

ce
That

IS

why
these

components
are

manufactured
WIth
utmost
care

To
clean
them
use

gasohne
and
blow
aIr
on

them

ChangIng
Jet
or
air

bleed
sIze

may

cause
III
vehICle
emIssIon
So

they
should
not

be

changed
theIr
numbers

Trouble

Shootmg

In
the

follOWIng
table
the

symptom
and

causes
of
carburetor
troubles
and
remedIes
for

them

are
hsted
to
faclhtate

qUIck
repaIrs

There

are
vanous
causes
of

engIne
trouble
It

sometImes

happens
that
the

completely
effec

tlve
carburetor
seems

apparently
to
have

some
troubles
when
electnc

systern
IS
defec

tIve
Therefore
whenever
the

engIne
has

troubles
electnc

system
must
be
checked
first

before

adjusting
the
carburetor

TROUBLE
SHOOTING

Troubles
POSSible
causes

Remedlc

Overflow
Dirt

accumulated
on
needle
valve
Clean
needle
valve

Fuel

pump
pressure
100

hIgh
RCpJlf

pump

Needle

valve
seat

Improper

Lap
or

replai
e

ExceSSIve
fuel

Fuel
overflows
See
above

I
l

onsumptlon

Each

mam
aIr
bleed

clogged
Clean

80

ruel

Sptem

Troubles

Power

shortage

Improper
IdlIng

Rough
engIne
Idle

or

eogme
stop

Engme
Idle
too
fast
Possible
causes

Gauge
plate
adjustment
mcorrect

Choke
valve
does
not

open

Outlet
valve
seat

of
accelerator

pump
1m

proper

Lmked

openmg
of

secondary
throttle
valve

too

early

each
mam

Jet
clogged

EaLh
throttle
valve
does
not

fully
open

Fuel

pump
operated
Improperly

uel
stramer

clogged

Vacuum

Jet
clogged

Power
vdlve

operated
Improperly

Slow

Jel
dugged

Fat
h
thronle
valve
does
not
close

Secondary
throttle
valve

operated
Im

properly

Eal
h
throttle
valve
shaft
wear

Packing
between
mamfold
and
carburetor

defective

Fuel
overflows

Incorrect
carburetor

adjustment
Idle

speed

Idle
miXture
choke

settmg

Incorrect
baSIC

1
OIt100

tunmg

Incorrect

automatic
temperature
control
air

cleaner

Defect
or
malfunction

of

Igmtlon
system

spark
plug
lugh
tenSion

cable
breaker

JX
Int

Ignition
COIl
etc

Trouble
In
throttle
lInk
and
cable

Incorred
throttle

opener
adjustment

Trouble
In

PCV
valve

Trouble
In
automatic

choke

Defect
or

malfunctIOn
of

Igmhon
s
stem

spark
plug
hIgh
tenSion
cable
breaker

pomt
Ignition
Call
elc
Remedies

Correct

adjustment

Adjust

Lap
or

replace

Adlust

Clean

Adjust

Repair

Clean

Clean

Adlust

Clean

Adlusl

Overhaul
and
dedn

Replace

ReplaLe
tlghtenlllg

See
the
fust
Item

Adjust
Idle

speed
mixture
dnd

tUllIng

Adjust
19mtlon
timing

Adjust
automatlL

temperature
control
air

cleaner

Adjust
or

replaLe
IgllltIun
system

Chel
k
throttle
hnk
and
Lable

Adjust
throttle

opener

Replace
PCV
vJlve

Adjust
auotmJtIL
l
hoke

Adjust
or

replac
e

IgllltIun
system

J

81

Fuel
I
em

Troubles

Engine
hesitatIOn

Car
knock
when

coastIng

EnglOe
does
not

start

82
POSSIble
causes

Eal
h
mam

Jet
slow

Jet
clogged

By

pdss
hole
die

pdssage
dogged

Emulsion
lube

dogged

Idhng
adlostment
mcorrect

Secondary
throttle
valve

operated
1m

properly

Incorrect
throttle

opener
adjustment

Trouble
m
PCV

valve

Defect
or

malfunction
of

Igmtlon
system

spark
plog
ugh
tenSIon
cable
breaker

pomt
IgmtIon
cod

etc

Fuel
overflows

No
fuel

IdlIng
adjustment
mearrect

Fast
Idle

adjustment
mcareeet

Damaged
antl
dlesehng
solenoId

BI
metal
rod
m

contact
WIth
bl
metal
case
RemedIes

Clean

Cledn

lube

lean

Correct

adjustment

Overhaul
and
clean

AdjUstlhroltle
opener

Replace
PCV
valve

Adjust
or

replace
IgJuhan
system

See
the
first
Item

Check

pump
fuel

pIpe
and
needle
valve

Correct

adjustment

Correct

adjustment

Replace

Adlust

Transmission

Worn

gears
shaft
and
or

heanng
Repl
ll
c

In
ufficlcnt

operatmg
stroke
due
to
worn
or
loose

shdmg

pdll
Repair
or

replal
c

Defective
or

damaged

synchronIzer
Replace

Gear

slips
out

of
mesh

In
the
most
cases
thiS
trouble
occurs
when
the
Interlock

plunger
check
ball
and
or

spnng
IS
worn
or
weakened
or

when
the
control

system
IS
defectIve
In
thiS
Cd
the
trouble
cannot
be

corrected

by
repldtlllg
gt
drs

and
therefore

trouble
shootmg
must
be

earned
out

carefully
It
should
also
be
noted
that

gear
slips
out
of
mesh
due
to
vlbralIon

generated
by
weakened
front
and
rear

engme
mounts

Worn
mterlock

plunger
Replal
c

Worn
check
hall
and
or

weakened
or
broken

sprmg
Replal
c

Worn
fork
rod
ball

groove
RepI

H
e

Worn
or

damaged
beanng
Repldce

Worn
or

damaged
gear
Repldl
c

NOise

When
nOIse

occurs
unoer
engine
Idling
and

stops
whde
the
clutch
IS

dlseng
lged
or
when
nOI
Olcurs
while

shlftmg

gears
It

may

Judged
that
the
nOIse

IS
from
the
tranSmll
lSIUn

Ino

ufllclenl
or

1mproper
lubncant
Add
od
or

replace
With

deSignated

oIl

Ollleaklllg
due
to
defectIve
011
seal
md

gasket
clogged
breather
etc
Clean
or

replace

Worn
beanng

High
hummmg
occurs
at
a

high
speed
Replace

Damaged
beanng
Cychc
knockmg
sound
occurs
alllo
at
a
low

speed
Replace

Worn
each

sphne
Replace

Worn
each

hushmg
Replace

108