O.S. engine FS-120S-E User manual

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1

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Ô

S

aneme

It

is

of

vital

importance,

before

attempting

to

operate

your

engine,

to

read

this

SAFETY

INSTRUCTIONS

AND

WARNINGS’

leaflet

and

to

strictly

adhere

to

the

advice

contained

herein.

Also,

please

SAFETY

INSTRUCTIONS

AND

WARNINGS

ABOUT

YOUR

O.S.ENGINE

(FOR

AIRCRAFT)

/\\

notes

read

through

the

instruction

leaflet

or

manual

supplied

with

the

engine,

so

as

to

familiarize

yourself

with

the

controls

and

other

|

°

This

engine

was

designed

for

model

aircraft.

Do

not

attempt

to

features

of

the

engine.

use

it

for

any

other

purpose.

keep

this

leaflet

and

the

engine

instructions

in

a

safe

place

so

that

|

°

Mount

the

engine

in

your

model

securely,

following

the

manu-

you

may

readily

refer

to

them

whenever

necessary.

It

is

suggested

that

any

instructions

supplied

with

the

aircraft,

radio-control

equip-

ment,

etc.,

are

accessible

for

checking

at

the

same

time.

Remember

that

your

engine

is

not

a

"

toy

",

but

a

highly

efficient

internal-combustion

machine

whose

power

is

capable

of

harming

you,

or

others,

if

it

is

misused

or

abused.

As

owner,

you,

alone,

are

responsible

for

the

safe

operation

of

your

engine,

so

act

with

discretion

and

care

at

all

times.

If

at

some

future

date,

your O.S.

engine

is

acquired

by

another

person,

we

would

respectfully

request

that

these

instructions

are

also

passed

on

to

its

new

owner.

W

The

advice

which

follows

is

grouped

under

two

headings

ac-

cording

to

the

degree

of

damage

or

danger

which

might

arise

through

misuse

or

neglect.

Cover

events

which

might

involve

serious(in

extreme

circumstances,

even

fatal)

injury.

Cover

the

many

other

possibilities,

gener-

ally

less

obvious

sources

of

danger,

but

which,

under

certain

circumstances,

may

also

cause

damage

or

injury.

e

Never

touch,

or

allow

any

object

to

come

into

contact

with,

the

rotating

propeller

and

do

not

crouch

over

the

engine

when

it

is

run-

ning.

e

A

weakened

or

loose

propeller

may

disintegrate

or

be

thrown

off

and,

since

propeller

tip

speeds

with

powerful

engines

may

exceed

600

feet(180

metres)

per

second,

it

will

be

understood

that

such

a

failure

could

result

in

serious

injury.

(see

‘NOTES’

section

relating

to

propeller

safety).

e

Model

engine

fuel

is

poisonous.

Do

not

alloow

it

to

come

into

contact

with

the

eyes

or

mouth.

Always

store

it

in

a

clearly

marked

container

and

out

of

the

reach

of

children.

*

Model

engine

fuel

is

also

highly

flammable.

Keep

it

away

from

naked

flame,

excessive

heat,

sources

of

sparks,

or

anything

else

which

might

ignite

it.

Do

not

smoke

or

allow

anyone

else

to

smoke,

near

to

it.

*

Never

operate

your

engine

in

an

enclosed

space.

Model

en-

gines,

like

automobile

engines,

exhaust

deadly

carbon-mon-

oxide.

Run

your

engine

only

in

an

open

area.

«

Model

engines

generate

considerable

heat.

Do

not

touch

any

part

of

your

engine

until

it

has

cooled.

Contact

with

the

muffler

(si-

lencer),

cylinder

head

or

exhaust

header

pipe,

in

particular,

may

result

in

a

serious

burn.

facturers’

recommendations,

using

appropriate

screws

and

locknuts.

°

Fit

an

effective

silencer(muffler).

Frequent

close

exposure

to

a

noisy

exhaust

(especially

in

the

case

of

the

most

powerful

high

-speed

engines)

may

eventually

impair

your

hearing

and

such

noise

is

also

likely

to

cause

annoyance

to

others

over

a

wide

area.

.

Fit

a

top-quality

propeller

of

the

diameter

and

pitch

specified

for

the

engine

and

aircraft.

Locate

the

propeller

on

the

shaft

so

that

the

curved

face

of

the

blades

faces

forward-i.e.

in

the

di-

rection

of

flight.

Firmly

tighten

the

propeller

nut,

using

the

cor-

rect

size

wrench,

e

Always

check

the

tightness

of

the

propeller

nut

and

retighten

it,

if

necessary,

before

restarting

the

engine,

particularly

in

the

case

of

four-stroke-cycle

engines.

If

a

safety

locknut

assembly

is

provided

with

your

engine,

always

use

it.

This

will

prevent

the

propeller

from

flying

off

in

the

event

of

a

"backfire",

even

if

it

loosens.

°

If

you

fit

a

spinner,

make

sure

that

it

is

a

precision

made

prod-

uct

and

that

the

slots

for

the

propeller

blades

do

not

cut

into

the

blade

roots

and

weaken

them.

e

Discard

any

propeller

which

has

become

split,

cracked,

nicked

or

otherwise

rendered

unsafe.

Do

not

attempt

to

repair

such

a

propeller:

destroy

it.

Do

not

modify

a

propeller

in

any

way,

un-

less

you

are

highly

experienced

in

tuning

propellers

for

spe-

cialized

competition

work

such

as

pylon-racing.

*

Use

an

electric

starter.

The

wearing

of

safety

glasses

is

also

strongly

recommended.

¢

Take

care

that

the

glow

plug

clip

or

battery

leads

do

not

come

into

contact

with

the

propeller.

Also

check

the

linkage

to

the

throttle

arm.

A

disconnected

linkage

could

also

foul

the

propel-

ler.

-

After

starting

the

engine,

carry

out

any

needle-valve

readjust-

ments

from

a

safe

position

behind

the

rotating

propeller.

Stop

the

engine

before

attempting

to

make

other

adjustments

to

the

carburettor.

e

Adjust

the

throttle

linkage

so

that

the

engine

stops

when

the

throttle

stick

and

trim

lever

on

the

transmitter

are

fully

re-

tarded.

Alternatively,

the

engine

may

be

stopped

by

cutting

off

the

fuel

supply.

Never

try

to

stop

the

engine

physically.

*

Take

care

that

loose

clothing

(ties,

shirt

sleeves,

scarves,

etc.)

do

not

come

into

contact

with

the

propeller.

Do

not

carry

loose

objects

(such

as

pencils,

screwdrivers,

etc.)

in

a

shirt

pocket

from

where

they

could

fall

through

the

propeller

arc.

*

Do

not

start

your

engine

in

an

area

containing

loose

gravel

or

sand.

The

propeller

may

throw

such

material

in

your

face

and

eyes

and

cause

injury.

°

For

their

safety,

keep

all

onlookers

(especially

small

children)

well

back

(at

least

20

feet

or

6

metres)

when

preparing

your

model

for

flight.

If

you

have

to

carry

the

model

to

the

take-off

point

with

the

engine

running,

be

especially

cautious.

Keep

the

propeller

pointed

away

from

you

and

walk

well

clear

of

specta-

tors.

e

Warning!

Immediately

after

a

glowplug-ignition

engine

has

been

run

and

is

still

warm,

conditions

sometimes

exist

whereby

it

is

just

possible

for

the

engine

to

abruptly

restart

if

the

propeller

is

casually

flipped

over

compression

WITHOUT

the

glowplug

battery

being

reconnected.

Remember

this

if

you

wish

to

avoid

the

risk

of

a

painfully

rapped

knuckle!

6-15

3-Chome

Imagawa

Higashisumiyoshi-ku

O.S.

ENGINES

mraco.tro.

osaka

546-0003

Japan

TEL.

(06)

6702-0225

©)

copyright

1995

by

O.S.Engines

Mfg.

Co.,

Ltd.

All

rights

reserved.

Printed

in

Japan.

FAX.

(06)

6704-2722

INSTRUCTIONS

FOR

O.S.

FS-120S-E

FOUR

STROKE

CYCLE

ENGINE

IMPORTANT

:

Before

attempting

to

operate

your

FS-120S-E,

please

read

through

these

instructions

so

as

to

familiarize

yourself

with

the

controls

and

other

features

of

the

engine.

Also,

pay

careful

attention

to

the

recom-

mendations

contained

in

the

"Safety

Instructions

and

Warnings"

leaflet

enclosed.

INSTALLATION

Use

sturdy

engine

mounting

beams:

i.e.

at

least

as

strong

as

would

be

used

for

a

two-stroke

engine

of

20cc,

or

greater,

displacement.

Make

sure

that

these

beams

are

firmly

integrated

with

the

airframe,

reinforcing

the

internal

sur-

rounding

structure

as

necessary

to

absorb

vibration.

Engine

installation

should

be

made

in

such

a

way

that

basic

main-

tenance,

including

the

checking

and

adjustment

of

valve

clearances,

can

be

conveniently

carried

out.

As

an

aid

to

aligning

the

engine

on

its

mounting

beams,

a

simple

mount-

ing

hole

template

is

supplied

with

the

engine.

As

an

alternative

to

horizontal

beam

mounting,

a

special

O.S.

radial

motor

mount

is

available,

as

an

optional

extra

part,

for

use

where

firewall

mounting

is

required.

SILENCER

ASSEMBLY

Installation

procedure

is

as

follows.

1.

Secure

the

exhaust

header

pipe

by

screwing

the

union-

nut

over

the

cylinder-head

exhaust-stub.

Adjust

the

header

pipe

to

the

required

angle,

then

tighten

the

union-

nut

firmly

with

the

17mm

wrench

supplied.

2.

Screw

the

silencer

onto

the

end

of

the

header

pipe

and

tighten

locknut

firmly.

Note:

It

is

advisable

to

apply

silicone

sealant

at

the

joints

to

prevent

leakage

of

exhaust

gas

and

loosening

of

nuts.

CARBURETTOR

The

needle-valve

and

throttle

lever

locations

are

inter-

Changeable

by

reversing

the

carburettor.

This

can

be

done

as

follows:

Remove

the

carburettor

carefully

by

unscrewing

the

two

screws

which

secure

both

carburettor

and

choke

valve.

(See

Photo

1.)

If

the

carburettor

remains

difficult

to

remove,

slightly

loosen

the

two

screws

which

secure

the

intake

pipe

to

the

cylinder

head.

After

reversing

the

carburettor,

re-fit

it

to

the

intake

pipe

gently,

taking

care

not

to

damage

the

O-ring

in

the

carbu-

rettor

by

using

force.

Intake

pipe

fixing

screws

“0”

ring

Carburettor

fixing

screws

Set

screw

Choke

lever

Hexagon

nut

Cap

screw

Choke

rubber

pad

Photo

1

CHOKE

VALVE

The

FS-120S-E

is

equipped

with

a

spring-loaded

choke

valve.

The

choke

valve

operating

lever

can

be

located

right

or

left

by

transposing

the

hexagon

nut

and

cap

screw.

After

mounting

the

engine

in

the

model,

secure

the

L-shaped

choke

rod

by

tightening

the

set-screw.

If

the

rod

supplied

is

too

long,

reduce

it

to

the

required

length.

If

the

rod

length

is

more

than

40mm

(1%

in.)

its

outer

end

should

be

Supported

to

avoid

vibration.

SPECIFICATIONS

Displacement

19.96

cc

(1.218

cu.in.)

Bore

30.4

mm

(1.197

in.)

Stroke

27.5

mm

(1.083

in.)

Practical

R.P.M.

2,000

~

11,000

r.p.m.

Output

1.9

BHP/11,000

r.p.m.

Weight

864

g

(30.5

oz.)

FUEL

TANK

The

suggested

fuel

tank

size

is

400cc

or

14

oz.

This

will

give

approximately

10

minutes

running

time

when

some

part-throttle

operation

is

included.

Locate

the

fuel

tank

so

that

the

centre

line

of

the

tank

is

10

to

15mm

below

the

centre

line

of

the

needle-valve.

Note:

If

the

model

is

left

unattended

with

the

fuel

tank

filled,

fuel

may

flow

into

the

carburettor,

causing

it

to

“flood”

and

making

the

engine

difficult

to

start.

Take

appropriate

action

to

prevent

this.

FUEL

The

FS-120S-E

runs

on

standard

commercially

available

model

glowplug

engine

fuel.

Fuels

containing

castor-oil

and/or

synthetic

lubricants

are

acceptable,

but

for

the

best

performance

and

reliability,

a

fuel

containing

5

—

15%

nitromethane

is

recommended.

For

consistent

performance

and

long

engine

life,

it

is

advisable

to

use

good

quality

fuel

containing

NOT

LESS

THAN

18%

lubricant.

(The

carburettor

is

adjusted

with

a

fuel

containing

20%

lubricant

when

the

engine

leaves

the

factory.)

i

Centre

line

CLH

oe

GLOWPLUG

An

O.S.

Type

”F”

glowplug

is

fitted

to

the

engine.

With

a

four-stroke

engine,

ignition

of

the

fuel

charge

takes

place

at

every

fourth

stroke

of

the

piston

instead

of

every

second

stroke.

Because

of

this,

some

conventional

two-

stroke

glowplugs

will

not

suit

this

engine.

For

general

use,

the

special

O.S.

Type

F

glowplug

is

recommended.

PROPELLER

The

choice

of

propeller

depends

on

the

design

and

weight

of

the

model

and

on

the

type

of

flying

envisaged.

Deter-

mine

the

best

size

and

type

after

practical

experiment.

As

Starting

points,

suggested

propellers

are

listed

below.

For

stunt

models

13x11~12,

14x10~11

15x8,

16x6~7,

17x6,

18x5~6,

14x7

(3-blade),

15x8

(3-blade)

For

scale

models

Note:

Slightly

smaller

or

larger

props

than

those

shown

in

the

list

can

be

used.

However,

it

should

be

noted

that

propeller

noise

will

increase

if

propeller

blade

tio

velocity

is

increased

(i.e.

due

to

higher

engine

r.p.m.

or

a

larger

prop

diameter).

For

safety,

keep

your

face

and

other

parts

of

the

body

well

away

from

the

propeller

when

starting

the

engine

or

adjust-

ing

the

needle-valve

while

the

engine

is

running.

Remember

that

the

propeller

turns

through

a

much

wider

arc

with

the

large

sized

propellers

that

this

engine

is

capable

of

driving.

Refer

to

the

“Safety

Instructions

and

Warnings”

leaflet

enclosed.

IMPORTANT:

Use

well

balanced

propellers

and

spinners

only.

An

unbalanced

propeller

or

spinner

causes

vibration

and

loss

of

power.

There

is

always

a

danger,

especially

with

nylon

pro-

pellers

(and

depending

on

engine

speed

and

weather

conditions),

of

the

propeller

fracturing

and

a

blade

flying

off

and,

obviously,

this

could

cause

serious

injury.

Therefore,

never

crouch

over

the

engine

when

it is

running

and

keep

all

onlookers

well

back

and

behind

the

model.

if

a

spinner

is

used,

make

sure

that

the

spinner

notches

are

large

enough

to

clear

the

propeller

blades

and

so

do

not

cut

into

and

weaken

the

blade

roots

when

the

propeller

nut

is

tightened.

WARNING:

There

is

also

a

risk,

particularly

with

four-stroke

engines,

of

the

propeller

flying

off

if

the

propeller

nut

loosens

due

to

detonation

or

“knocking”

when

the

engine

is

run

too

lean

or

under

too

heavy

a

load.

Obviously

this

can

also

be

very

hazardous.

To

combat

this

danger,

we

have

developed

the

special

Safety

Propeller

Locknut

Assembly

supplied

with

the

FS-120S-E.

This

prevents

the

propeller

from

flying

off,

even

if

the

propeller

itself

should

slip

or

loosen.

1.

Ream

the

propeller

centre

hole

to

8mm

dia.

Make

sure

that

the

propeller

is

properly

balanced.

2.

Fit

the

propeller

sleeve-nut

and

washer

to

the

propeller,

screw

onto

the

shaft

and

tighten

firmly

with

17mm

wrench

supplied.

3.

Finally,

insert

the

Safety

Propeller

Locknut.

Tighten

Locknut

firmly

(but

not

with

excessive

force)

using

14mm

wrench.

(see

Fig.

2)

IMPORTANT:

Regardless

of

the

type

of

propeller

fixing

used,

make

a

habit

of

al-

ways

checking

the

tightness

of

the

propeller

before

starting

the

engine.

Remember

that,

especially

with

wooden

propellers,

there

is

a

tendency

for

the

material

to

shrink,

or

for

it

to

be

reduced

by

the

serrated

face

of

the

drive

hub.

Drive

hub

Propeller

washer

\

STARTING

It

is

preferable

to

use

a

heavy-duty

electric

starter.

1.

Firstly,

fit

a

spinner

so

that

an

electric

starter

can

be

used.

The

O.S.

special

locknut

set

for

spinner,

that

is

available

as

an

optional

part,

enables

you

to

fit

a

spinner

securely

and

easily.

2.

Open

the

throttle

so

that

the

throttle-arm

is

at

one-

Starting

position

quarter

of

its

full

throw.

Fig.

3

(see

Fig.

3)

(a)

lf

a

silencer

pressurized

fuel

system

is

employed,

set

the

needle-valve

2⁄2

turns

open

from

the

fully

closed

position.

(b)

If

a

silencer

pressurized

fuel

system

is

not

employed,

set

the

needle-valve

3

turns

open

from

the

fully

closed

position.

3.

Energize

the

glowplug

and

apply

the

electric

starter

after

making

sure

that

the

battery

leads

are

properly

connected

for

counter-clockwise

rotation.

If

the

power

of

your

starter

is

insufficient

to

immediately

rotate

the

engine

freely,

turn

the

propeller

clockwise

(‘backwards’)

until

compression

is

felt,

then,

with

the

propeller

in

this

posi-

tion,

try

the

starter

again.

This

will

enable

the

kinetic

energy

of

the

rotating

propeller

to

assist

in

carrying

the

engine

through

its

compression

stroke.

Also,

make

sure

that

your

starter

battery

is

in

good

condition

and

fully

charged.

CAUTION:

Never

apply

an

electric

starter

with

the

choke

closed.

Such

an

action

will

cause

an

excess

quantity

of

fuel

to

be

drawn

into

the

cylinder

and

result

in

an

hydraulic

lock

that

may

damage

the

engine.

4.

When

the

engine

starts,

keep

it

running,

initially,

with

the

original

needle-valve

setting

while

steadily

moving

the

throttle

to

the

fully

open

position.

If

the

engine

slows

down

because

the

mixture

is

excessively

rich,

close

the

needle-valve

slowly

until

the

engine

runs

evenly.

Then

disconnect

the

battery

from

the

glowplug

and

close

the

needle-valve

slowly

so

that

revolutions

increase.

Adjust

the

needle-valve

gradually.

Abrupt

adjustment

of

the

needle-valve

may

cause

the

engine

to

stop.

Note:

Excess

fuel

in

the

carburettor

may

drip

into

the

engine

com-

partment

when

the

choke

valve

is

reopened.

Therefore,

it

is

advisable

to

drill

a

drain

hole

in

the

bottom

of

the

engine

bay

or

cowling

and

to

apply

fuelproof

paint

to

the

surrounding

surfaces

to

prevent

fuel

from

penetrating

the

airframe

struc-

ture.

RUNNING-IN

(‘‘Breaking-in’’)

All

internal

combustion

engines

benefit,

to

some

degree,

from

extra

care

when

they

are

run

for

the

first

few

times

—

known

as

running-in

or

breaking-in.

This

is

because

the

working

parts

of

a

new

engine

take

a

little

time

to

settle

down

after

being

subjected

to

high

temperatures

and

Stress.

However,

as

O.S.

engines

are

made

with

the

aid

of

the

finest

modern

precision

machinery

and

from

the

best

and

most

suitable

materials,

only

a

very

short

and

simple

running-in

procedure

is

required

and

can

be

carried

out

with

the

engine

installed

in

the

model.

For

running-in,

use

the

same

sized

propeller

as

you

intend

for

flying

your

model.

Running-in

procedure

is

as

follows:

Start

the

engine

and

run

it

for

about

5

seconds

at

around

maximum

r.p.m.,

then

open

the

needle-valve

%

turn

to

produce

a

rich

mixture

for

cooler,

slower

running,

and

run

for

,20

seconds

at

this

setting.

Keep

the

throttle

fully

open,

using

only

the

needle-valve

to

reduce

speed.

Repeat

this

procedure,

alternately

running

the

engine

fast

and

slow

with

the

needle-valve,

but

gradually

extending

the

short

periods

of

maximum

speed

running

until

two

full

tanks

of

fuel

are

consumed.

Note:

Take

care

to

avoid

dusty

and

sandy

locations.

Dust

and

grit

drawn

into

the

engine

will

seriously

damage

its

working

parts.

Following

the

initial

break-in

on

the

ground,

the

engine

should

be

given

a

period

of

moderately

rich

running

in

the

air.

For

the

first

flights,

set

the

needle-valve

rich,

consistent

with

adequate

take-off

power

and

steady

level

flight

and,

if

necessary,

readjust

the

throttle

trim

on

the

transmitter

so

that

the

engine

does

not

stop

when

the

throttle

is

fully

closed.

With

each

successive

flight,

close

the

needle-valve

slightly,

until,

at

the

end

of

10

flights,

the

needle-valve

is

set

for

maximum

power.

The

carburettor

can

now

be

adjusted

for

optimum

throttle

performance

following

the

instructions

given

in

the

next

section.

Note:

Remember

that,

while

the

engine

is

being

run-in

and

the

needle-valve

is

set

on

the

rich

side,

the

carburettor

cannot

be

expected

to

show

its

best

response.

Therefore,

avoid

abrupt

throttle

operation

at

this

stage.

ADJUSTING

THE

CARBURETTOR

The

carburettor

of

your

FS-120S-E

has

been

factory

set

for

the

approximate

best

result,

but

the

settings

may,

in

some

cases,

vary

slightly

in

accordance

with

fuel

and

climatic

conditions.

If

the

desired

throttle

response

is

not

obtained

after

the

completion

of

the

running-in

period,

the

carburettor

should

be

re-adjusted

as

follows.

Please

refer

to

Photos

2

and

3.

Three

adjustable

controls

are

provided

on

this

carburettor.

@

The

Needle-Valve:

For

adjusting

the

mixture

strength

when

the

throttle

is

fully

open.

@®

The

Mixture

Control

Screw:

For

adjusting

the

mixture

strength

at

part-throttle

and

idling

speeds,

to

obtain

steady

idling

and

smooth

acceleration

to

medium

speeds.

è

The

Throttle

Stop

Screw:

For

establishing

the

minimum

idling

speed.

Mixture

control

screw

Needle

valve

Rotor

guide

screw

f-

Photo

2

E

1.

Set

the

throttle

lever

1/4

open

from

the

fully

closed

position

(see

Fig.

3)

and

start

the

engine

in

the

usual

way.

It

is

preferable

to

have

the

throttle

only

slightly

open,

to

avoid

unnecessarily

high

revolutions

when

the

engine

starts.

2.

Now

open

the

throttle

fully

and

gradually

close

the

needie-valve

until

the

engine

is

running

at

its

optimum

rp.m.

in

the

air.

The

needle-valve

setting

at

this

time

will

be

1/8

to

1/4

open

from

the

maximum

r.p.m.

setting.

Note:

Make

sure

that

the

engine

is

fully

“‘run-in’’

before

operating

it

continuously

at

full

power.

(See

RUNNING

IN

section.)

3.

Having

set

the

needle-valve

as

described

above,

close

the

throttle

and

run

the

engine

at

idling

speed

for

approxi-

mately

5

seconds,

then

steadily

move

the

throttle

to

the

fully

open

position

by

means

of

the

throttle

servo.

(a)

lf,

at

this

point,

the

engine

hesitates

before

picking

up

speed,

with

a

low-pitched

exhaust

note

and

an

excess

of

exhaust

smoke,

it

is

probable

that

the

idling

mixture

is

too

rich.

In

this

case,

it

will

be

necessary

to

turn

the

mixture

control

screw

clockwise

about

45

degrees.

(b)

If,

on

the

other

hand,

the

engine

hesitates

or

even

appears

to

cease

firing

for

an

instant,

before

in-

creasing

speed,

it

is

probable

that

the

idling

mixture

is

too

lean.

In

this

case,

it

will

be

necessary

to

turn

the

mixture

control

screw

counter-clockwise

about

90

degrees,

then

turn

it

clockwise

45

degrees.

Turn

the

mixture

control

screw

30

to

45

degrees

at

a

time

in

the

early

stages.

When

the

response

improves,

turn

the

mixture

control

screw

10

to

15

degrees

at

a

time.

Carry

out

adjustments

progressively

and

patiently,

remembering

the

symptoms

of

rich

and

lean

running,

quoted

above,

until

the

engine

responds

quickly

and

positively

to

the

throttle.

4.

The

throttle

stop

screw

is

for

fixing

the

minimum

idling

speed.

If,

after

carrying

out

mixture

adjustments,

the

idling

speed

is

found

to

be

too

high,

the

throttle

stop

screw

should

be

turned

counter-clockwise

until

the

desired

idling

speed

is

obtained.

Note:

Once

the

correct

carburettor

settings

have

been

established,

it

should

be

unnecessary

to

alter

them.

Such

slight

needle-valve

readjustments

as

may

be

required

to

compensate

for

varia-

tions

in

atmospheric

conditions,

will

not

normally

affect

the

other

two

controls.

Slight

readjustments

may

be

necessary

for

optimum

performance

if

different

types

of

fuel,

glow-

plugs

or

propellers

are

used.

In

this

case,

begin

by

flying

the

model

with

the

needle-valve

approximately

1/8

to

1/4

turn

open

from

the

peak

r.p.m.

as

a

safety

measure,

then

readjust

as

necessary.

REALIGNMENT

OF

MIXTURE

CONTROL

VALVE

In

the

course

of

making

carburettor

adjustments,

it

is

just

possible

that

the

Mixture

Control

Valve

may

be

inadver-

tently

screwed

in

or

out

too

far

and

thereby

moved

beyond

its

effective

adjustment

range.

lts

basic

setting

can

be

reestablished

as

follows:

The

basic

(factory)

setting

is

as

shown

in

the

main

sketch,

i.e.

with

the

shoulder

portion

‘A’

exactly

at

a

tangent

to

the

throttle

rotor

hole.

To

return

the

Mixture

Control

Valve

to

its

original

position,

first

screw

in

the

Mixture

Control

Valve,

while

looking

into

the

rotor

hole.

Then

gradually

unscrew

the

Mix-

ture

Control

Valve

until

‘A’

is

precisely

tangential

to

the

rotor

hole

(i.e.

so

that

‘A’

and

‘B'

are

superimposed)

as

in

Throttle

‘A

rotor

hole

an)

the

main

sketch.

B

Fig.

4

CARBURETTOR

CLEANLINESS

The

correct

functioning

of

the

carburettor

depends

on

its

small

fuel

orifices

remain-

ing

clear.

The

minute

particles

of

foreign

matter

that

are

pre-

sent

in

any

fuel

can

easily

partially

obstruct

these

orifices

and

upset

mixture

strength

so

that

engine

per-

formance

becomes

erratic

and

unreliable.

=

It

is

recommended

that

fuel

is

passed

through

a

filter

when

the

tank

is

filled

and

that

a

good

in-line

filter

is

installed

between

the

fuel

tank

and

carburettor

and,

furthermore,

that

this

filter

is

frequently

cleaned

to

remove

dirt

and

lint

that

accumulate

on

the

filter

screen.

Finally,

occasionally

remove

the

needle-valve

holder

from

the

carburettor,

using

the

wrench

supplied,

and

extract

any

remaining

foreign

matter

that

may

have

lodged

in

the

location

shown

in

Photo

3.

Throttle

stop

screw

Dirt

and

fibrous

matter

mostly

accumulate

here.

Photo

3

VALVE

CLEARANCE

ADJUSTMENT

Valve

clearances

are

correctly

set

before

any

O.S.

four-

stroke

engine

leaves

the

factory

and,

in

normal

use,

will

seldom

require

adjustment.

However,

if,

after

a

considera-

ble

amount

of

running

time

has

accumulated,

a

loss

of

power

is

detected,

or

if

the

engine

has

to

be

disassembled

or

repaired

as

a

result

of

a

crash,

valve

clearances

should

be

checked

and

readjusted

as

necessary.

For

checking

and

adjusting

the

valve

clearances,

a

valve

adjusting

kit,

contain-

ing

two

feeler

gauges

and

two

wrenches,

is

available

as

an

optional

accessory.

Note:

Valve

clearances

on

this

engine.

must

be

checked

and

reset

only

WHEN

THE

ENGINE

IS

COLD.

1.

Remove

the

rocker

cover

by

unscrewing

two

Allen

screws

from

the

rocker

box

on

top

of

the

cylinder

head.

2.

Turn

propeller

until

compression

is

felt,

then

turn

it

one

quarter

turn

and

stop.

Both

valves

should

now

be

closed.

3.

The

required

valve

clearance

is

between

0.04

mm

and

0.10

mm

(.0015

to

.004

in.)

measured

between

the

valve

stem

and

rocker-arm.

Use

the

0.04

mm

(thinner

one)

and

0.10

mm

(thicker

one)

feeler

gauges

to

check

clearance.

The

0.04

mm

feeler

should

pass

through

the

gap:

the

0.10

mm

gauge

should

not.

4.

If

the

gap

is

found

to

be

less

than

0.04

mm

or

more

than

0.10

mm,

carefully

slacken

the

locknut

on

the

rocker-

arm

with

the

5

mm

wrench

supplied,

turn

adjusting

screw

with

1.5

mm

Allen

key

to

open

or

close

gap,

then

retighten

locknut.

Finally,

re-check

gap

and

readjust

if

necessary.

IMPORTANT:

Incorrect

valve

clearances

may

cause

difficult

starting

(due

to

valve

not

closing

properly)

or

loss

of

power

(due

to

valve

not

opening

sufficiently).

NEEDLE

VALVE

EXTENSION

The

needle-valve

supplied

with

this

engine

is

designed

to

in-

corporate

an

extension

so

that,

when

the

engine

is

enclosed

within

the

fuselage,

the

needle-valve

may

be

adjusted

from

the

outside.

An

L-shaped

rod,

of

1.6

—

1.8

mm

dia.

and

appropriate

length,

should

be

inserted

into

the

needle’s

centre

hole

and

secured

by

tightening

the

set-screw

in

the

needle-valve

knob

with

the

small

Allen

key

provided.

CARE

AND

MAINTENANCE

To

ensure-that

you

obtain

long

life

and

peak

performance

from

your

engine,

observe

the

following.

1.

Avoid

running

the

engine

under

dusty

conditions.

It

necessary,

lay

a

sheet

of

plywood

or

hardboard

in

front

and

under

the

nose

of

the

model

when

starting

the

engine.

2.

Foreign

matter

in

the

fuel

can

cause

the

carburettor

jet

to

be

partially

clogged.

Therefore:

rinse

out

the

fuel

tank

with

methanol

or

fuel

before

installing

it

fit

a

fuel

filter

in

the

fuel

delivery

tube

between

tank

and

carburettor

e

fit

a

fuel

filter

to

the

outlet

of

your

squeeze

bottle,

or

to

the

pump

inlet

if

you

use

a

manual

or

electric

pump

e

do

not

leave

your

fuel

container

open

needlessly

e

check

filters

periodically

and

clean

them

when

necessary.

3.

Do

not

leave

raw

fuel

in

the

engine

at

the

conclusion

of

a

flying

session:

it

may

cause

corrosion.

The

best

practice

is

to

disconnect

the

delivery

tube

from

the

carburettor

while

the

engine

is

running.

Remaining

fuel

in

the

tank

should

also

be

drained

off.

IMPORTANT:

After

the

engine

has

run

dry,

liberally

inject

corrosion-inhibiting

oil

or

light

machine

oil

into

the

crankcase,

via

the

breather

hole,

until

excess

oil

runs

from

.behind

the

drive

hub

when

the

engine

is

pointed

downwards.

Rotate

the

crankshaft

to

distribute

the

oil

to

the

bearings,

etc.

Failure

to

carry

out

this

procedure

may

cause

interna!

rusting,

resulting

in

engine

malfunction

and

voiding

the

warranty.

4.

Clean

the

exterior

of

the

engine

with

a

clean

cotton

cloth.

If

this

is

not

done,

oil

and

dirt

will

burn

onto

the

outside

of

the

engine

each

time

it

is

run

and

the

engine

will

soon

become

blackened.

5.

If

the

engine

is

not

to

be

used

for

a

while

(more

than

two

months)

remove

the

glowplug

and

rinse

out

the

interior

with

kerosene

(not

gasoline),

by

rotating

the

crankshaft.

Shake

out

residue,

then

inject

corrosion-

inhibiting

oil

or

light

machine-oil

through

the

exhaust

pipe

and

breather

hole,

again

rotating

the

shaft

to

distri-

bute

the

protective

oil

to

all

working

parts.

6.

Avoid

unnecessary

dismantling

of

your

engine.

PARTS

LIST

Code

No.

|

Description

||

Code

No.

|

Description

45501020

Crankcase

|

45530010

|

Crankshaft

Bearing

(Rear)

45501110

Cam

Cover

|

45231100

|

Camshaft

Bearing

45502011

Crankshaft

|

45560030

|

Intake

Valve

Assembly

45503100

Cylinder

Liner

|

45560040

|

Exhaust

Valve

Assembly

45503210

Piston

|

45561010

Rocker

Arm

Assembly

45503400

Piston

Ring

ee

Rocker

Support

Assembly

45504020

Cylinder

Head

(w/Valve

Ass'y)

|

45562010

|

Camshaft

45505010

Connecting

Rod

|

45566101

Push

Rod

Cover

Assembly

45506010

Piston

Pin

|

45569420

Intake

Pipe

|

29017004

Piston

Pin

Retainer

|

45581000

Carburettor

Complete

45507010

Cover

Plate

|

45484000

|

Choke

Valve

Assembly

45508030

Drive

Hub

(w/Key)

|

45525001

|

Silencer

Assembly

45508200

Woodruff

Key

|

71615009

|

Glow

Plug

Type

"

F

"

45514010

|

Gasket

Set

||

#72140400

|

EX-502

Exhaust

Header

Pipe

(120

IN)

29031009

|

Crankshaft

Bearing

(Front)

||

*72140500

|

EX-502

Exhaust

Header

Pipe

(120

C)

*

Optional

parts

The

specifications

are

subject

to

alteration

for

improvement

without

notice.

GS.

ENGINES

mreco.ro

6-15

3-chome

Imagawa

Higashisumiyoshi-ku

Osaka

546-0003,

Japan

TEL.(06)702-0225

FAX.(06)704-2722

©

Copyright

1989

by

O.S.

Engines

Mfg.

Co.,

Ltd.

All

rights

reserved.

Printed

in

Japan

60090510-19805