light DATSUN B110 1973 Service Workshop Manual

EMISSION
CONTROL
AND

TUNE
UP

Capacity

Maximum
3
3
L
X

US

gal
y

Imp
gal

2
3
L
US

gal
f

Imp
gal
Minimum

Make
sure
that

engine
oil
is

not
deteriorated
with

cooling
water
or

gasoline
Drain

and
refill
the
oil

if

necessary

Notes

a
A

milky
oil
indicates
the

presence
of

cooling

water

Find
the
cause
for

necessary
corrective
action

b
Oil
with

extremely
low

viscosity
indicates

dilution
with

gasoline

2
Check

oil
level
If
found
below
L

mark
refill
to

H
mark

on

gauge

Fig
ET
3

Checking

engine
oil
level

Replacing
oil
filter

The
oil
ftIter
is
of
a

cartridge
type
The
oil
filter

can
be

removed

using
oil
ftIter
wrench
STl9320000
Check
for
oil
leaks

through
gasketed

flange
If

any

leakage
is
found

retighten
slightly
If

necessary

replace

filter
as
an

assembly

2
When

installing
an
oil
filter

tighten

by
hand

Note
Do
not

overtighten
oil
filter
or
oil

leakage
way

result

Changing
engine
coolant
L

L
C

Nissan

long
life
coolant

LLC
is
an

ethylene
glycol
base

product

containing

chemical
inhibitors
to

protect
the

cooling
system
from

rusting
and
corrosion

The
L
L
C

does
not
contain

any

glycerine
ethyl
or

methyl
alcohol
It
will
not

evaporate

or
boil

away
and

can
be
used
with
either

high
or
low

temperature
thermostat
It

flows

freely
transfers
heat

efficiently
and
will
not

clog
the

passages
in
the

cooling

system
The
LL

C
must
not
be

mixed
with
other

products
This
coolant
can
be
used

throughout
tlie

seasons
of
the

year

Whenever

any
coolant
is

changed
the

cooling
system

should
be
flushed
and

refilled
with
a
new

coolant

Check
the
level
J

Percent
Boiling
point

0
9

kgfcm2
Freeze

concen

tration
Sea
level

cooling
sys
protection

tern

pressure

30
1060

C
I

240C
15OC

221OF
255OF
5OF

50
IUY
C
1270C
35
C

2280
F
2610F
3IOF

DC
OF

0

321

10
14

20141

50
58
I

I

I

I

1

I

I

1
30
1
22

40

401

40
10
30
50
20

EGOOl

Fig
ET
4
Protection

concentration

ET
3

ENGINE

4
Install

a

timing
light
on
No

cylinder
spark

plug

wire
and
install

a
tachometer

5

Set

idling
speed
to

approximately
800

rpm

6

Check

ignition
timing
if

it
is
50BTDC
Before

Top
of

Dead
Center

by
the

use
of

timing
light

If

necessary
adjust
it

as
follows

Loosen
set
screw
to
such
an
extent
that

distributor
can

be
moved

by
hand

2

Adjust
ignition
timing
to
50BTDC

3

Lock
distributor

set
screw
and
make
sure
that

timing

is
correct

Fig
ET
9

Checking
ignition
timing

Ignition
timing
degree
50
B
T
D
C

Checking
or

replacing
distributor

breaker

point
condenser
and

spark

plugs

Distributor
breaker

point

Check
distributot
breaker

points
for
abnormal

pitting

and
wear

Replace
if

necessary
Make
sure

they
are
in

correct

alignment
for
full
contact
and
that

point
dwell

and

gap
are
correct
Clean
and

apply
distributor

grease

to
earn
and
wick

Note
Do
not

apply
grease
excessively
Distributor

Point

gap
0
45
to
0
55
mm

0
018

to
0
Q22
in

49
to
55

degrees
Dwell

angle

ET004

Fig
ET
10

Checking
distributor

point
gap

Condenser

I

Clean
outlet
of
condenser
lead

wire
and
check
for

loose

set
screw

Retighten
if

necessary

2

Check
condenser

capacity
with
a

capacity
meter

Condenser
insulation
resistance

may
be
also
checked

using
a

tester

by
adjusting
its

range
to
measure

large

resistance
value
When
condenser
is
normal
the

tester

pointer
swings
largely
and

rapidly
and
moves

gradually

back

to
the

infmite
side
When
the

pointet
does

not

stay
still
or
it

points
zero
in
resistance

replacement
is

necessary

Condenser

capacity

0

221LF
Micro
Farad

Condenser
insulation
resistance

5
Mn

Mega
ohms

Spark

plugs

Remove

and
clean

plugs
in

a
sand
blast
cleaner

Inspect

each

spark
plug
Make
sure
that

they
are
of
the

specified
heat

tange
Inspect
insulator
for
cracks
and

chips
Check

both
center
and

ground
electrodes
If

they
are

excessi
ely
worn

replace
with
new

spark

plugs
File
center
electrode
flat

Set
the

gap
to
0
8
to

0

9
rom
0

031
to
0
035
in

using
the

proper

adjusting

tool

Tighten
plugs
to

1
5
to
2
0

kg
m
11
0
to
15
0

ft

lb

torque

ET
6

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

ENGINE

3
Connect
a
3

way
connector
a

manometer
and
a

cock
or
an

equivalent
3

way
change
cock
to
the

end

of
the

vent
line

4

Supply
fresh
air
into
the

vapor
vent
line

through
the

cock
little

by
little

until
the

pressure
becomes
368

mm

Aq
14
5
in

Aq

5
Shut
the
cock

completely
and

leave
it
that

way

6
After
2
5
minutes
measure
the

height
of
the

liquid

in
the
manometer

7
Variation
of

height
should
remain
within
254

mmAq
1
0
in

Aq

8
When
the
filler

cap
does
not
close

completely
the

height
should

drop
to
zero
in
a

short
time

9

If
the

height
does
not

drop
to
zero
in
a

short
time

when
the

filler

cap
is
removed
it
is
the
cause
of
the

stuffy
hose

Note
In

case
the
vent
line
is

stuffy
the

breathing
in

fuel

tank
is
not

thoroughly
made
thus

causing

insufficient

delivery
of
fuel
to

engine
or

vapor

lock

It
must
therefore
be

repaired
or

replaced

3

way

connector

Cock

Air

Manometer
Vapor
liquid

seearator

Flow

guide
valve

E

CQ29

Fig
ET
40

Checking
evaporative
emission
control

system

Checking
flow

guide
valve

I
Disconnect
all
hoses
connected
to
the

flow

guide

valve

2
While
lower

pressure
air
is

pressed
into

the
flow

guide
valve
from
the
ends
of
vent
line
of

fuel
tank
side

the
air
should

go
through
the
valve
and
flow
to

crankcase

side
If
the
air
does
not
flow
the

valve
should

be

replaced
But
when
the
air
is
blown
from

crankcase

side
it
should
never
flow

to
the
other

two
vent
lines

3
While

the
air
is

pressed
into

the
flow

guide
valve
from
the
carburetor
air

cleaner
side

it
flows
to
the

fuel

tank
side
and
or

crankcase
side

4

This
valve

opens
when
the

inner

pressure
is
10

mmHg
0
4
in

Hg
In

case
of

improper

operations
or

breakage
replace
it

From

carburetor

air
cleaner

From
fuel
tank

i

I
I

ti

i

i

1
1

i
To
ran
kcase

E
C030

Fig
ET
41
Flow

guide
valve

Checking
fuel
tank

vaCCUID
relief

valve

operation

Remove
fuel
filler

cap
and
see
if
it
functions

properly

as

follows

Wipe
clean
valve

housing
and
have
it
in

your
mouth

2

Inhale
air
A

slight
resistance

accompanied
by
valve

indicates
that
valve
is
in

good
mechanical
condition
Note

also
that

by
further

inhaling
air
the
resistance
should
be

disappeared
with
valve
clicks

3

If
valve
seems
to
be

clogged
or
if
no
resistance
is
felt

replace
cap
as
an

assembled
unit

T

1i
v

rUr1f
AlI
j

r
I
r
tLMJJl

rr
L

cc

11

J
v

II

4J
L

Valve
I

valve
seat

Spring
Valve

housing

Fig
ET

42
Fuel

filler
cap

ET
24

EMISSION
CONTROL
AND

TUNE
UP

Trouble

shooting
procedure
on

starting
circuit

Switch

on
the

starting
motor

with

light
put
on

When

light
goes
off
or
dims

considerably

a
Check

battery

b
Check
cable
for
connection

c

Check
starter
motor

When

light
stays
bright

a
Check

wiring
connection
between

battery

and
starter
motor

b

Check
starter
switch

c
Check
starter
motor

ENGINE
WILL
CRANK
NORMALLY
BUT
WILL
NOT
START

In

this
case

following
trouble
causes

may
exist
In

the
most
causes

ignition
system
or

fuel

system
is
in
trouble

Ignition
system
in

trouble

Fuel

system
in
trouble

Valve
mechanism
does
not

work

properly

Low

compression

Check

spark
plug
first
in
accordance

with
the

following

procedure

Disconnect

high
tension

cable
from
one

spark
plug
and
hold

it

about
10
rom

0
4
in

away
from
the

engine
metal

part
and

crank
the

engine

Good

spark
occurs
a
Check

spark
plug

b
Check

ignition
timing

Check
fuel

system

d
Check

cylinder
compression

No

spark
occurs
Check

the
current
flow

in

primary
circuit

Very
high
current

Inspect
primary
circuit
for
short

Check
breaker

point
for

operation

Low

or
no
current
Check
for
loose
terminal
or
disconnection

in

primary
circuit

Check
for

burned

points

Ignition
system
in
trouble

Burned
distributor

point
Repair
or

replace

Improper
point
gap
Adjust

Defective

capacitor
Replace

Rotor

cap
and
rotor
leak

Replace

ET
27

ti

EMISSION
CONTROL
AND

TUNE
UP

Mechanical

knocking

Crankshaft

bearing

knocking

Connecting
rod

bearing

knocking

Piston
and

cylinder

noise

Piston

pin
noise

Water

pump
noise

Others
Defect
or

malfunction
of

ignition
system

spark
plug
high
tension
cable
breaker

point
ignition
coil
etc

This

strong
dull
noise
increases
when
the

engine
is
accelerated
To
locate

the

place

calise
a
misfire

on
each

cylinder
If
the
noise

stops
by
the

misfire
this

cylinder
generates

the
noise

This
is
a
little

higher
pitched
noise

than
the

crankshaft

knocking
and
also
increases

when
the

engine
is
accelerated
Cause
a

misfire
on
each

cylinder
and
if
the
noise

diminishes
almost

completely
this
crank

shaft

bearing
generates
the

noise

When

you
hear
an

overlapping
metalic
noise

which
increases
its

magnitude
with
the
revo

lution
of
the

engine
and

which
decreases
as

the

engine
is

warmed

up
this
noise
is
caused

by
the

piston
and
cylinder
To
locate
the

place
cause
a
misfire
on
each

cylinder

This
noise
is

heard
at
each

highest
and

lowest
dead

end
of
the

piston
To
locate

the

place
cause
a
misfire
on
each

cylinder

This

noise

may
be

caused

by
the
worn
or

damaged
bearings
or

by
the
uneven

surface

of

sliding
parts

An

improper
adjustment
of
the
valve
clear

ance

Noise

of
the

timing
chain

An

excessive
end

play
on
the
crankshaft

Remarks

Disengage
the
clutch

slightly
and

this

noise
will

stop

Wear
on
the
clutch

pilot
bushing

Remarks
This
noise
will
be
heard
when
the

clutch
is

disengaged

ET
31
Adjust
or

replace
ignition
syste
m

This
is

caused

by
the
wom
or

damaged

bearings
or

unevenly
worn
crankshaft

Renew
the

bearings
and

adjust
o

change
the

crankshaft

Check
the
lubrication

system

Same
as
the

case
of
crankshaft
bear

ings

This

may
cause
an
abnormal

wearing

of
the

cylinder
and
lower

compression

which
in

turn
will

cause
a

lower

output
power
and
excessive

consump

tion
of
oiL

Overhaul
the

engine

This

may
cause
a

wear
on
the

piston

pin
or

piston
pin
hole

Renew
the

piston
and

piston
pin
as

sembly

Replace
the

water

pump
with
a
new

one

Readjust

Adjust
the
tension

of
the
chain

Disassemble
the

engine
and
renew
the

main

bearing
bushing

Renew
the

bushing
and

adjust
the

drive
shaft

ENGINE

CYLINDER
BLOCK

The

cylinder
block
in

a
mono
block

special
casting

structure

adopts
five

bearing

support
system

The
A
12

Engine
is

provided
with

baffle

plate
and
steel

net
to

reduce
oil

consumption
the
steel
net

scoops
oil

j
y

r

0

Q

0

T

Fig
EM
2

Cylinder
block

Fig
EM
3

Cylinder
block

CRANKSHAFT

The
crankshaft
is
made
of

special
forged
steel
and

provided
with

a
high

capacity
balance

weight
The

crankshaft

improves
engine
quietness
and

durability
t

high
speed
operation

The
main

bearing
are
lubricated
from
oil
holes
which

intersect
the
main
oil

gallery
in

parallel
with
the

cylinder

bores
v

Fig
EM
4

Crankshaft

PISTON
AND
CONNECTING
ROD

The

newly
designed
lightweight
piston
is

of
cast

aluminum

slipper
skirt

type

The
A
12

Engine
uses
concave
head

pistons
The

piston

pin
is
of
a

special
steel
hollow

type
and
is
connected
to

the

piston
in

a
full

floating
fit
and

to
the

connecting
rod

in

press
fit

The

connecting
rod
is

made
of

forged
steeL
Full

pressure
lubrication
is

directed
to
the

connecting
rods

through
drilled
oil

passages
from
the

adjacent
main

bearing

journal

Oil
holes

on
the

connecting
rod

journals
are
designed

so

that
oil
is

supplied
to

give
maximum
lubrication

just

before
full

bearing
load
is

applied

J

oO

o

e

Fig
EM
5
Piston
and

connecting
rod

CYLINDER
HEAD

The

cylinder
head
is

made
of

light
and

strong

aluminum

alloy
with

good
cooling
efficiency
A

special

aluminum
bronze
valve
seat
is
used
on
the
intake
valve

while

a

special
cast
valve
seat
is
installed
on
the
exhaust

valve
These

parts
are
hot

press
fitted

EM
2

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

FUEL
SYSTEM

c

Oke
valve

1

Or

Rubber
band

Fig
EF
2B

Adjusting
choke
unloadeT

Hi
metal

setting

Measurement
of
bi
metal
heater

resistance
Install
the

bi
metal
cover
in

place
on

the
carburetor
Make

sure
that

the
resistance

across
the

terminal
and
the
carburetor

body

is
in

the

range
from
8
6

to
9
0

ohms
Measure

the

resistance
without

electric
current

through
the

heater
and

at
about

210e
700F

Note
Use
an
accurate

measuring
instrument
such
as
a

wheatstone

bridge

2
Bi
metal

cover

setting

Position
the
hi

metal
cover
until
the
index

mark
is

aligned
at
the
middle

point
of
the
scale

Note
When
somewhat
over
choked
set
bi
metal

cover

after

turning
it
clockwise

slightly
Fig
EF
29

Setting
hi
metal
cover

EF
17