fuel consumption DATSUN PICK-UP 1977 Service Manual

Yellow

line

Spark
delay
valve
to

distributor

Spark
delay
valve
to
vacuum
tube

Distributor

to
vacuum
tube

Vacuum
tube
to
carburetor

Vacuum
tube
to
canister

Green
line

Anti

backfire
valve
to
intake
mani

fold

Air

control
valve
to

emergency
air

relief
valve

Intake
manifold
to
vacuum
hose

connector

Intake

manifold
to
canister

CHECKING
ENGINE

COMPRESSION

COMPRESSION
PRESSURE

TEST

I
Warm

up
engine
sufficiently

2
Disconnect

all

spark
plugs

3
Disconnect
anti

dieseling
solenoid

valve
connector

4

Properly
attach
a

compression

tester
to

spark

plug
hole
in

cylinder

being
tested
Engine
Tune

up

I

ET010
Different

compression
in
two
or

more

cylinders
usually
indicates

an

improperly
seated
valve
or
broken

piston
ring

9
Low

compression
in

cylinders
can

result
from
worn

piston
rings
This

condition

may
usually
be

accompanied

by
excessive

fuel

consumption

TEST
RESULT

If

compression
in

one
or
more

cylinders
is
low

pour
a
small

quantity

of

engine
oil
into

cylinders
through

the

spark
plug
holes
and
retest
com

pression

I

If

adding
oil
increases
the
com

pression
pressure
the
chances
are
that

rings
are

faulty

2

If

pressure
stays
low

probable

cause
is

that
valve
is

sticking
or

seating

improperly

3
If

cylinder
compression
in

any

two

adjacent
cylinders
is

low
and
if

adding
oil
does
not

help
the

compres

sian
there
is

leakage
past
the

gasket

surface

Oil
and
water
in

combustion
cham

bers

can
result
from

leakage

IGNITION
AND

FUEL
SYSTEM
Fig
ET
10

Teding

compression

pressure

5

Depress
accelerator

pedal
to

open

throttle
and
choke
valves

Note
Do

not

pump
pedal

6
Start

engine
as

quickly
as

pos

sible

7

Compression
pressure

kg
cm2

psi
at

rpm

Standard

12
0

171
350

Minimum

9

0
128
350

8

Cylinder
compression
in

cylinders

Should
not
be
less
than

80
of

highest

reading

CONTENTS

CHECKING
BATTERY
ET
9

CHECKING
DISTRIBUTOR
CAP
ROTOR

CHECKING
AND

ADJUSTING
IGNITION
AND
CONDENSER
ET
11

TIMING
ET
10

CONDENSER
ET
11

ADJUSTING
IGNITION
TIMING
ET10

ADJUSTING
CARBURETOR
IDLE
RPM

CHECKING
AND
REPLACING
SPARK
PLUG
ETlO
AND
MIXTURE
RATIO
ET

11

CHECKING
DISTRIBUTOR
OPERATING
IDLE

LIMITER
CAP
ET
12

PARTS
AND

IGNITION
WIRING
ETlO
CHECKING
CARBURETOR
RETURN
SPRING
ET

12

BREAKER
POINTS

lNon
California
models

ET
10
CHECKING
CHOKE
MECHANISM

AI
R

GAP
lCalifornia
models
ET11
Choke

plate
and

linkage
ET13

DISTRIBUTOR
ET
11
CHECKING
FUEL

LINES

IGNITION
WIRING

ET
11
Hoses

pipings
connections
etc

ET
13

REPLACING
FUEL
FILTER
ET
13

CHECKING
BATTERY

Check

electrolyte
level
in

each
bat

tery
cell
I
Unscrew

each
filler

cap
and

inspect
fluid
level
If
the
fluid
is
low

add
distilled
water
to

bring
the
level

up
approximately
10
to
20
mm
0
39

H
9
to
0
79

in
above
the

plates
Do
not

overfill

2
Measure
the

specific
gravity
of

battery
electrolyte

Engine
Tune

up

EC284

When

installing
this
valve

ensure

that
it

properly
oriented
This
valve

should
be

replaced
periodically
Refer

to
Maintenance
Schedule

I

To

distribut0
From

carburetor

Yl
r

EC278
l

Fig
ET
24
Operation
of
spark
delay

value

I

I

Carburetor
side

Distributor
side

rJmlL
lr

EC346

Fig
ET
25
Checking

spark
delay
value
Distributor
side

Brown

lOne
way
umbrella
valve

2
Sintered
metal
disc

Fig
ET
23
Spark
delay
valve

INSPECTION

I
Remove

spark
delay
valve

2
Blow
air

through
port
on

carbure

tor
side
then

through
the

other
port

on
distributor
side

Spark
delay
valve

is
in

good
condition
if
when

finger
is

placed
over

port
on
distrib
side

ajr
flow
resistance
is

greater
than
that

on
the
other

side
See

Figure
ET
25

3
If
a
considerable
air
flow
resist

ance
is
felt
at

port
on
distributor
side

in

step
2

above
and

if
the
condition
of

spark
delay
valve
is

questionable
dip

port
on
carburetor

side
into
a

cup

fIlled
with
water
Blow
air

through
the

other

port
Small
air
bubbles
should

appear

EC279

Fig
ET
26

Checking
spark
delay
ualue

Note
Be

careful
to

avoid

entry
of
oil

or
dirt
into
valve

ET
15
CHECKING

AUTOMATIC

TEMPERATURE

CONTROL
AIR

CLEANER

1
Air
cleener
element

Viscous

paper
type
air
cleaner
ele

ment
does
not

require
any
cleaning

opera
tion

until
it
is

replaced
periodi

cally
Brushing
or

blasting
operation

will

cause

clogging
and
result
in
enrich

ment
of
carburetor
mixture
and

should
never
be
conducted
For
reo

placement
interval
of
air
cleaner
ele

ment
refer

to
Maintenance
Schedule

2
Hot

elr
control
system

In
warm
wealher
it
is
difficult
to

find
ou

t
malfunction
of
hot
air
control

system
In
cold
weather
however

malfunction
of
air
control
valve
d

e
to

disconnection
or
deterioration
of
vacu

um
hose
between
intake
manifold
and

vacuum
motor
and
insufficient
dura

bili

ty
of
air

con
trol
valve
will
cause

insufficient
automatic
control

opera

tion
for
intake
air
and
result
in

engine

disorder

including

I

Stall
or
hesitation
of

engine

opera

tion

2

Increase
in
fuel

consumption

3
Lack
of

power

These

phenomena
reveal
malfunc

tionof
hot
air
control

system
If
these

phenomena
should
occur
check
hot

air
control

system
as
described
in
the

following
before

carrying
ou

t

inspec

tion
of
carburetor

2
1
Vacuum
hoses

Intake
manifold
to
3

way
connec

tor
3

way
connector
to

temperature

sensor
3

way
connector
to
idle
com

pensator
temperature
sensor
to

vacu

um
motor

1

Check
that
vacuum
hoses
are
se

curely
connected
in

correct

position

2
Check
each
hose
for
cracks
or

distortion
hose

clip
for
condition

Condition

NOISY

ENGINE

Car

knocking

Mechanical

knocking

Crankshaft

bearing

Imocking

Connecting
rod

bearing
knocking

Piston
and

cylinder

noise

Piston

pin
noise

Water

pump
noise

Air

pump
noise

Others
Engine
Tune

up

Probable
cause

Overloaded

engine

Carbon

knocking

Timing
knocking

Fuel

knocking

Preignition
misusing
of

spark
plug

This

strong
dull
noise
increases
when

engine

is

accelerated
To
locate
the

place
cause
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

Imocking
and
also
increases

when

engine
is
accelerated
Cause
a
misfire

on
each

cylinder
and
if
the
noise
deminishes

almost

completely
this
crankshaft

bearing

generates
the
noise

When

you
hear
an

overlapping
metalic
noise

which
increases
its

magnitude
with
the

revolution
of

engine
and
which
decreases
as

engine
is
warmed

up
this
noise
is
caused

by

piston
and
cylinder
To
locate
the

place

cause
a
misfire
on
each

cylinder

This
noise
is

heared
at
each

highest
and

lowest
dead
end
of

piston
To
locate

the

place
cause
a

misfire
on
each

cylinder

This
noise

may
be
caused

by
worn
or

damaged
earings
or
by
the
uneven
surface

of
sliding

parts

Damaged
air

pump

An
improper
adjustment
of
valve
clearance

Noise
of

timing
chain

An
excessive
end

play
on
crankshaft

Noisy
E
F
E

valve
shaft

Wear
on
clutch

pilot
bushing

Note
This
noise
will
be
heared
when

clutch
is

disengaged

ET31
Corrective
action

Use

right
gear
in
driving

Disassemble

cylinder
head
and

remove

carbon

Adjust
ignition
timing

Use

specified
octane
fuel

Use

specified
spark
plug

This
is

caused

by
worn
or

damaged
bearings

or
unevenly
worn
crankshaft
Renew

bearings
and

adjust
or

change
crankshaft

Check
lubrication

system

Same
as
the
case
of
crankshaft

bearings

This

may
cause
an
abnormal

wearing
of

cylinder
and
lower

compression
which
in

turn
will
cause
a
lower
out

put
power
and

excessive

consumption
of
oil

Overhaul

engine

This

may
cause
a
wear
on

piston
pin
or

piston
pin
hole

Renew

piston
and

piston

pin
assembly

Replace
water

pump
with
a
new
one

Repair
or

replace

Adjust

Adjust
the
tension
of
chain

Disassemble

engine
and
renew
main
bearing

Repair

Renew
bush

and

adjust
drive
shaft

Condition

ABNORMAL

COMBUSTION

backfue
afterflre

run
on
etc

Improper

ignition
timing

Fuel

system
out
of

order

Faulty
cylinder
head
etc

Others

EXCESSIVE
OIL

CONSUMPTION

Oilloak

Excessi
lo
oil

consumption

Others
Engine
Tune

up

probable
cause

Improper
ignition
timing

Improper
heat

range
of

spark
plugs

Damaged
carburetor

or
manifold

gasket

backfue
afterfire

Clol
l
ed
carburetor

jet

Improper
function
of

the
float

Uneven

idling
Run
on

Improperly
adjusted
B

C
D
D

set

pressure

Malfunction
of
anti

dieseling
solenoid
valve

Malfunction
of
auio
choke

Improperly
adjusted
valve
clearance

Excess
carbon
in

combustion
chamber

Damaged
valve

spring
backfire
afterflre

Malfunction
of

A
T
C

air
cleaner

Inoperative
ariti
backfue
valve

Loose
oil
drain

plug

Loose

or
damaged
oil

pan
gasket

Loose
or

damaged
chain
cover

gasket

Worn
oil
seal
in
front
and
rear
of
crankshaft

Loose
or

damaged
locker
cover

gasket

Improper
tightening
of
oil
filter

Loose
or

damaged
oil

pressure
switch

Cylinder
and

pioton
wear

Improper
location
of

piston
ring

gap
or

reversely
assembled

piston
ring

Damage
piston
rings

Worn

piston
ring
groove
and

ring

Fatigue
of
valve
oil
seal

lip

Worn
valve

stem

Inadequate
quality
of

engine
oil

Engine
overheat

ET32
Corrective
action

Adjust
ignition
timing

Use

specified
spark
plugs

Replace
them
with
new

parts

Disassemble
carburetor
and
check
it

Adjust
the
level
and
check
needle
valve

Adjust

Adjust

Check
or

replace

Adjust

Adjust

Remove
head
and

get
rid
of
carbon

Replace
it
with
a
new
one

Check
for
loose
vacuum
hoses

Replace
if

necessary

Replape

Tighten
it

Renew

gasket
or

tighten
it

Renew

gasket
or

tighten
it

Renew
oil
seal

Renew

gasket
or

tighten
it
but
not
too

much

Renew

gasket
and

tighten
it
with
the

proper

torque

Renew
oil

pressure
switch
or

tighten
it

Overhaul

cylinder
and
renew

piston

Remoun
t

piston
rings

Renew

rings

Repair
or
renew

piston
and

cylinder

Renew

piston
and

piston
ring

Replace
seal

lip
with
a

new
one

Renew
valve
or

guide

Use
the

designated
oil

Previously
mentioned

r

AIR
CLEANER

1
Loosen

bolts

securing
air
cleaner

to
air
cleaner
bracket

2
Loosen
air

cleaner
lock
bolt
and

remove
air

cleaner
from
carburetor

Disconnect
the

following
hoses
when

dismounting
air

cleaner

Under
hood
air
inlet

hose

Hot
air
inlet

hose

Vacuum

hose
Sensor
to
intake

manifold

Vacuum
hose
Sensor
to
vacuum

motor

Vacuum
hose

Idle

compensator
to

intake
manifold

Hose
Air

pump
to
air
cleaner

Hose
AB
valve

to
air
cleaner

Hose
Carburetor
to
air

cleaner

Blow

by
hose
Air

cleaner
to

rocker

cover

Hose
Air

control
vaive
to
air

cleaner
California

models

only

3
To

install

reverse
the
removal

procedure

INSPECTION

1
AIR
CLEANER

ELEMENT

Viscous

paper
type
air
cleaner

ele

ment
does
not

require
any
cleaning

operation
until
it

is

replaced
periodi

cally
Brushing
or

blasting

operation

will
cause

clogging
and

result
in
enrich

ment

of
carburetor
mixture

and

should
never
be

conducted
For

reo

placement
interval
of
air

cleaner
ele

ment
refer
to
Maintenance
Sched

ule

2
HOT

AIR

CONTROL
SYSTEM

In

warm
weather
it
is

difficult
to

find

out
malfunction
of
hot
air
control

system
In

cold
wea
thee

however

malfunction
of
air
control
valve

due
to

disconnection
or

deterioration
of

vacu

um

hose
between
intake
manifold
and

vacuum
motor
and

insufficient
dura

bility
of
air
control
valve

will
cause

insufficient
automatic
control

opera

tion

for
intake
air
and

result
in

engine

disorder

including

I

Stall

or
hesitation
of

engine

oper

ation

2

Increase
in

fuel

consumption

3

uck
of

power
Engine
Fuel

These

phenomena
reveal
malfunc

tion
of
hot
air
control

system
If
these

phenomena
should
occur
check
hot

air
control

system
as

described
in
the

following
before

carrying
out

inspec

tion

of
carburetor

2
1
Vacuum

hose

Intake
manifold
to
3

way
connec

tor
3

way
connector
to

temperature

sensor
3

way
connector
to

idle
com

pensator
temperature
sensor
to
vacu

um

motor

I

Check
that

vacuum
hoses
are

se

curely
connected
in

correct

postion

2

Check
each
hose
for

cracks
or

distortion

hose

clip
for

condition

Note

Vacuum
hose

position
R
H

side
of
Nissan

mark
on
the

top
of

sensor
is
for

intake
manifold
L
U

side
of

the
mark

is
for

vacuum

motor

2
2
Vacuum

motor

I

With

engine
stopped
disconnect

fresh
air

duct

Place
a
mirror

at
the
end
of
air

cleaner
inlet

pipe
as
shown
and

check

to

see
if
air

con
trol
valve

is
in

correct

position

EF213

Fig
EF
11

Inspecting
valve

position

Air

control
valve
is
in

correct

posi

tion
if
its
under
hood
air

inlet
is

open

and
hot
air
inlet
is

closed
Check
air

control
valve

linkage
for

condition

2

Disconnect

vacuum
motor
inlet

vacuum
hose
and
connect

another

hose
to
the
inlet
to

apply
vacuum
to

vacuum
motor
Vacuum
can
be

ap

plied
by
breathing
in
the

hose
end

as

shown

Place
a
mirror

at
the

end
of
air

cleaner
inlet

pipe
and

check
to

see
if

air

control
valve

is
in
correct

position

EF
6
EF217

Fig
EF
12

Inspecting
valve

position

Correct

position
of
air

control
valve

is

the
reverse
of

paragraph
J
above
Air

control
valve
is
in
correct

position
if

under
hood
air
inlet
is

closed
and
hot

air

inlet
is

open

3
With

hot
air

inlet
in

open
posi

tion

as
described
in

paragraph
2

above

pinch
vacuum
hose
with

fingers

and
cut
off
air

from
vacuum
hose
In

this
condition
check
that
air

control

valve

maintains
the

condition
de

scribed
in

step
2

for
more
than
30

seconds
and
that
hot
air

inlet
is

open

If

diaphragm
spring
actuates
the
air

control
valve

by
its

spring
force
to

open
under
hood
air
inlet

within
30

seconds

replace
vacuum
motor
as
an

assembly
since
this

may
be

resulted

from

air
leak
at
vacuum
motor
dia

phragm

2
3
Temperature
ensor

Check

temperature
sensor
for
func

tion

by

proceeding
as
follows
Be

sure

to

keep
engine
cold
before

starting

test

I

With

engine
off

check
air

control

valve
for
condition
In

this
case
under

hood
air

inlet
is

open
Use
a
mirror

for

inspection
as
2
2
1

above

2

Start

engine
and

keep
idling

Immediately
after

engine
starting

check
air
control
valve
for

correct

position
as
described
above
In

this

case
correct

position
of

air
control

valve

is
the
reverse
of
2
2
I

under

hood
air

inlet
is

closed
and
hot

air

inlet
is

open

3
Check
that
air
control
valve

grad

ually
opens
to
under
hood
air

inlet

side
as

engine
warms

up
When
en

vironmental

temperature
around
tern

perature
sensor
is

low

spend
more

time

for

engine
warming
up
operation

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

Engine
Fuel

toms
and

causes
of
carburetor
troubles

and

remedies
for
them

are
listed
to

facilitate

quick
repairs

There
are
various
causes
of

engine

malfunctions
It
sometimes

happens

that
a
carburetor
which
has
no
fault
TROUBLE

DIAGNOSES
AND

CORRECTIONS

In
the

following
table
the

syml

Condition

Probable
cause

Overflow
Dirt
accumulated
on

needle
valve

Fuel

pump
pressure
too

high

Needle
valve

improperly
seated

Excessive
fuel

consumption
Fuel
overflow

Slow

jet
too

large
on
each
main

jet

Main
air
bleed

clogged

Choke
valve
does
not

open

fully

Outlet
valve
seat
of
accelerator

pump

improper

Linked

opening
of

secondary
throttle
valve

opens
too

early

Power

shortage
Main

jets
clogged

Every
throttle
valve
does
not

open
fully

Idling

adjustment
incorrect

FIICI
tr

clogged

Vacuum

jet

clogged

Air

c1eane

clogged

Diaphragm
damaged

Power
valve

operating
improperly

Altitude

compensator
setting
incorrect
Cali

fornia

models

Improper
idling
Slow

jet
clogged

Every
throttle

valve
does
not
close

Secondary
throttle
valve

operating
im

properly

Throttle
valve

shafts
worn

Packing
between

manifold
carburetor

fauJiy

Manifold
carburetor

tightening
improper

Fuel
overflow

B

C
D
D

adjustment
incorrect

Vacuum
control
solenoid

damaged

Stuck
anti
stall
dash

pot

EF

36
appears
to
have

some

problems
when

actually
the

electric

system
is
at
fault

Therefore
whenever

the

engine
is

mal

functioning
the
electrical

system

should
be
checked
rust
before

adjust

ing
carburetor

Corrective
action

Clean
needle
valve

Repair
pump

Re

place

See
condition
overflow

Replace

Clean

Adjust

Lap

Adjust

Clean

Adjust

AdjusL

pa
ir

Clean

Clean

Replace

Adjust

Correct
H
L
lever

position

Clean

Adjust

Overhaul
and

clean

Replace

Replace
packing

Correct

tightening

See
l
ondition
ov

rl1ow

Adjust

Replace

Replace