O.S. engine FS-40S Setup guide

It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-6 of this booklet and to strictly
adhere to the advice contained therein.
●Also, please study the entire contents of this
instruction manual, so as to familiarize yourself
with the controls and other features of the
engine.
Keep these instructions in a safe place so that
you may readily refer to them whenever
necessary.
It is suggested that any instructions supplied
with the aircraft, radio control equipment, etc.,
are accessible for checking at the same time.
●
●

2 ~ 6
7
8
9
11 ~ 12
13 ~ 14
15
~ 21
21
27 ~ 29
30
31
10
12
SAFETY INSTRUCTIONSAND WARNINGS
ABOUT YOUR O.S. ENGINE
INTRODUCTION,BASIC ENGINE PARTS
INSTALLATION
INSTALLATION OF CHOKE ROD, NEEDLE VALVE
EXTENSION, EXHAUST PIPE ADJUSTMENT(FS-26S)
SILENCER,
LINKAGE OF THROTTLE LEVER
BEFORE STARTING
FUELAND PRESSURE LINES
ADVICE ON SELECTION OF FUEL,
GLOEPLUG & PROPELLER
STARTING THE ENGINE
CONTENTS
RUNNING -IN
CARBURETOR
CARBURETOR AIR-BLEED ADJUSTMENT
TROUBLE SHOOTING WHEN THE
ENGINE FAILS TO START
VALVE ADJUSTING
CARE AND MAINTENANCE
THREE VIEW DRAWING
ENGINE EXPLODED VIEW
CARBURETOR EXPLODED VIEW
& PARTS LIST
GENUINE PARTS &ACCESSORIES
MEMO
22
~ 23
24
25 ~ 26
32 ~ 35
36
37
38
1

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.
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.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
The advice which follows is grouped under two headings according to the
degree of damage or danger which might arise through misuse or neglect.
WARNINGS NOTES
These cover events which
might involve serious (in
extreme circumstances, even
fatal) injury.
These cover the many other
possibilities, generally less obvious
sources of danger, but which, under
certain circumstances, may also
cause damage or injury.
2

WARNINGS
Model engine fuel is poisonous. Do not
allow it to come into contact with the eyes
or mouth.Always store it in a
clearlymarkedcontainerand
out of the reach of children.
Never operate your engine in an en-
closed space. Model engines, like auto-
mobile engines, exhaust deadly carbon-
monoxide. 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 (silencer),
cylinder head or exhaust
header pipe, in particular,
may result in a serious burn.
•
•
•
•
Never touch, or allow any object to come
into contact with, the rotating
propeller and do not crouch
over the engine when it is
running.
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).
•
Model engine fuel is also highly
flammable. Keep it away from open flame,
excessive heat, sources of sparks, or
anythingelsewhichmightignite
it.Donotsmokeorallowanyone
else to smoke, near to it.
•
3

NOTES
•
•
•
•
•
This engine was designed for model
aircraft. Do not attempt to use it for any
other purpose.
Mount the engine in your model securely,
following the manufacturers' recommenda-
tions, using appropriate screws and lock-
nuts.
Be sure to use the silencer (muffler)
supplied with the engine. Frequent
exposure to an open exhaust may
eventually impair your hearing.
Such noise is also likely to cause
annoyance to others over a wide area.
Install 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 direction of flight.
Firmly tighten the propeller nut, using the
correct size wrench.
If you remove the glowplug from the engine
and check its condition by connecting the
battery leads to it, do not hold the plug with
bare fingers.Use an appropriate tool or a
folded piece of cloth.
4

NOTES
•
•
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 install a spinner, make sure that it is
a precision made product and that the
slots for the propeller blades do not cut into
the blade roots and weaken them.
Preferably, use an electric starter. The
wearing of safety glasses is also strongly
recommended.
•
•Discard any propeller which has become
split, cracked, nicked or otherwise rendered
unsafe. Never attempt to repair such a
propeller: destroy it. Do not modify a propeller
inanyway,unlessyouarehighlyexperienced
in tuning propellers for specialized
competition work such as pylon-racing.
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 propeller.
After starting the engine, carry out any
needle-valve readjustments from a safe
position behind the rotating propeller. Stop
the engine before attempting to make other
adjustments to the carburettor.
•
•
5

NOTES
•
•
•
•
•
Adjust the throttle linkage so that the engine
stops when the throttle stick and trim lever
on the transmitter are fully retarded.
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 meters) 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 spectators.
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

•Silencer Body
•Choke rod
•Silicone tubing
FS-26S FS-40S
INSTALLING THE GLOWPLUG
Carburetor
Install washer on glowplug and
insert carefully into cylinder-
head, making sure that it is not
cross-threaded before tightening
firmly.
BASIC ENGINE PARTS
The FS Series engines are up-to-date
overhead-valve four-stroke-cycle engines
formodel aircraft useand arethe outcome of
a long period of technical development. The
FS Series engines are produced by the
world's oldest and largest model engine
manufacturing company; a company which
also pioneered the quantity production of
model four-cycle engines.
Drive Hub
Crankcase
Silencer
Rocker Cover
INTRODUCTION
Glow plug
Washer
Accessories
•Silencer Assembly
•Choke rod
•Silicone tubing
Exhaust pipe
Propeller nut
Propeller
Washer
Cover plate
Glow plug
Fuel inlet
Breather nipple
Choke valve
7

INSTALLATION How to fasten the mounting screws.
Hardwood mounting beams
O.S. radial motor mount
(cast aluminum)
Tighten second nut firmly
down onto first nut.
Tighten this nut first.
Steel washer
3.5mm steel nuts
for FS-40S
Spring washer or
lock washer
Hardwood such as
cherry or maple.
Spring washer
3.5mm steel Allen screw
for FS-40S
Front view
CORRECT
Side view
Top surfaces are in
the same plane. Re-align the surfaces
as necessary
INCORRECT
Top surfaces are not
in the same plane. Opposite beam
Top surfaces
are not in the
same plane.
Engine does
not rest firmly.
Rigid hardwood
(e.g. maple)
At least
15mm(19/32") for FS-40S
At least 12mm
(1/2") for FS-26S
Installation in the model
A typical method of beam
mounting is shown below,left. O.S. radial motor mount
(Available as an optional extra part.
See parts list)
Make sure that the mounting beams are parallel
and that their top surfaces are in the same plane.
3mm steel nuts
for FS-26S
3mm steel screw
for FS-26S
3.5mm steel screw
for FS-40S
3mm steel Allen screw
for FS-26S
8

The FS Series engines are equipped with self-
reopening choke valves.
Cut the choke rod (supplied) to the length indicated,
then secire the rod by tightening the set screw, using
1.5mm Allen wrench (supplied), after installing the
engine.
INSTALLATION OF CHOKE ROD
Choke rod 1.5mm
Allen key
Set-screw
Choke rod
approx.
7mm approx.
2mm
Frame sides
of fuselage
NEEDLE VALVE EXTENSION
The needle-valve supplied with this engine is
designed to incorporate an extension so that, when
the engine is enclosed within the fuselage, the
needle-valve may be adjusted from the outside. Cut
the L-shaped rod supplied to the required length,
insert it into needle's centre hole and secure it by
tightening the set-screw in the needle-valve knob with
1.5mm. Allen key supplied.
Set-screw
1.5mm Allen key
The direction of the exhaust pipe may be altered in
accordance with individual installation requirements.
The angle is easily adjusted by loosening the nut that
secures the exhaust pipe to the culinder head. Use
the 10mm spanner supplied. Recheck the tightness of
the nut after the engine has been run, but take care
not to touch the exhaust-pipe as it becomes very hot.
EXHAUST PIPE ADJUSTMENT(FS-26S)
Releasing the
choke rod allows
the choke valve
to open.
9

SILENCER
The FS-26S and FS-40S are supplied with silencers
as standard equipment.
Installation for FS-26S
Slide the silencer over the exhaust pipe, and secure it
with two set-screwssupplied with the silencer. Re-
check tightness of screws when engine is hot.
Installation for FS-40S
Screw the exhaust header pipe into the exhaust port
until it "bottoms", then unscrew it just sufficiently to
achieve the required exhaust outlet angle. Secure the
pipe in this position by tightening the locknut firmly
against the cylinder head with the wrench supplied.
Then, screw the silencer onto the end of the header
pipe and tighten locknut firmly. Re-check tightness of
locknuts when engine is hot.
LINKAGE OF THROTTLE LEVER
First, ensure that the throttle rotor is fully closed when
the throttle-lever is in the closed position. Adjust rotor
stop screw if necessary. Then couple the lever to the
throttle-servo so that the rotor is fully closed when the
transmitter throttle stick and trim lever are in the fully
retarded position.
BEFORE STARTING
Tools, accessories, etc.
The following items are necessary for operating the
engine.
1 Fuel
Model glowplug engine fuel of good quality, preferably
containing a small percentage of nitromethane. (See
"Advice on selection of fuel, glowplug and propeller")
2 Glowplug
O.S. Type F glowplug is installed in the engine.
3 Propeller
Suggested propellers are shown in the ADVICE ON
SELECTION OF FUEL & PROPELLER section.
10

4 Glowplug battery
The power source for heating the glowplug may be
either a large heavy-duty 1.5volt dry cell, or preferably,
a 2-volt rechargeable lead-acid cell (accumulator).
1.5 volt heavy-duty
dry battery or 2 volt rechargeable lead-acid cell (at least 5Ah)
If a 2-volt cell is employed,
use a resistance wire, as
shown, to reduce applied
voltage, otherwise element
will overheat and burn out.
Resistance coil
(nichrome wire)
Adjust applied voltage by changing the position of clip on
resistance coil until glowplug element is glowing bright red.
Battery leads
Raise
voltage to
increase
brightness.
Lower voltage to
reduce brightness.
Warning (Very hot)
Never touch the nichrome wire while the battery is
connected.
5 Plug wrench
Used for tightening glowplug.
The O.S. long plug wrench is available
as an optional accessory.
For tightening
glowplug
Battery leads
6 Battery leads
These are used to conduct current from the battery to
the glowplug. Basically, two leads, with clips, are
required, but, for greater conve-
nience, twin leads with special
glowplug connectors, as shown on
the right, are commercially available.
7 Fuel tank
For installation in the model, a 120cc(4.2oz.)
for FS-26S, a 150cc(5oz.) for FS-40S tank is
suggested.
8 Fuel bottle or pump
For filling the fuel tank, a simple,
polyethylene "squeeze" bottle, with a
suitable spout,is all that is required.
Alternatively, one of the purpose-made
manual or electric fuel pumps may be
used to transfer fuel directly from your
fuel container to the fuel tank.
Fuel bulb
Manual
Electric
Fuel pumps
11

Fuel Can Filter
3
11 Silicone tubing
This is required for the connection
between the fuel tank and engine.
10 Fuel can filter
Install a filter in the outlet line of your
refuelling container to prevent entry of
foreignmatterintothefueltank.(Refer to
of STARTING THE ENGINE section.)
9 Electric starter and starter battery
An electric starter is recommended
for starting.
FUEL AND PRESSURE LINES
Fuel level
Muffler to tank pressure line
Connect suitable lengths of silicone tubing, as
illustrated, after installing the engine.
Attention to tank height
Note: When cutting silicone tubing···
Locate the fuel tank so the top of the tank is
5-10mm(1/4-3/8") above the level of theneedle-valve.
5-10mm
Silicone tubing
Use knife or razor blade Do not use wire cutters
or pliers.
*If you should need to clean the silicone tubing, use methanol
or glow-fuel, not gasoline or kerosene.
Silencer (muffler) pressurized fuel system
To reduce variation in fuel "head" and ensure steady
fuel delivery at the carburettor, it is advisable to employ
a silencer (muffler) pressurized fuel system, i.e. to use
the silencer outlet nipple to pressurize the fuel tank as
shown at left.
12

Fuel
Use a good quality commercial fuel or one of the
blendsshown inthetable. Fuel"A" issuitablefor
running-in and ordinary use. Fuel "B" is for use
when more power is required and for improved
flexibility. Note that even a small quantity of
nitromethane (3-5%) will improve flexibility,
making the needle-valve adjustment less critical
and improving throttle response. Use only
materials of the highest purity. Synthetic oils are
permissible but are less tolerant of a "lean run"
thancastor-oil.If, therefore, asyntheticlubricant
is used in the fuel, readjust the needle-valve to
a slightly richer setting, as a safety measure, in
case the fuel/air mixture becomes too lean
through maneuvers in flight. higher nitro fuel is
used,theengine shouldbechecked outtomake
surethatit is sufficientlyrun-in to operateonthat
particular fuel without overheating. Do not use
fuels containing less than 18% lubricant.
ADVICE ON SELECTION OF FUEL, GLOWPLUG & PROPELLER
AB
75%
20%
5%
65%
20%
15%
Methanol
Castor Oil
Nitromethane
Model engine fuel is poisonous. Do not
allow 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 open 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.
Reminder!
PROPELLER
Suggested propeller sizes are given in the table. As
the ideal propeller diameter, pitch and blade area vary
according to the size, weight and type of model, final
propeller selection will require in flight
experimentation.
13

9x6 ~ 7
FS-26S Trainer & Sport
Never touch, or allow any object to come into
contact with, the rotating propeller and do not
crouch over the engine when it is running.
Sport & Aerobatic
Reminder!
GLOWPLUG
The FS-26S and FS-40S are supplied with an O.S.
Type F glowplug, specially designed for O.S. four-
stroke engines.
The role of the glowplug
With a glowplug engine, ignition is initiated by the
applicationofa1.5-voltpowersource.Whenthebattery
isdisconnected,theheatretainedwithinthecombustion
chamber remains sufficient to keep the plug filament
glowing,therebycontinuingtokeeptheenginerunning.
Ignition timing is 'automatic' : under reduced load,
allowing higher rpm, the plug becomes hotter and,
appropriately, fires the fuel/air charge earlier;
conversely,atreducedrpm,theplugbecomecoolerand
ignition is retarded.
FS-40S
9x6
~ 7,10x6,10.5x6
8x6(3blade)
10x7
~ 7.5,11x6
9x7(3blade)10x7,10.5x6,11x7
12x5
~ 6,10x7(3blade)
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of
nitromethane unless more is essential for racing
events.
Do not run the engine too lean and do not leave the
battery connected while adjusting the needle.
However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
When to replace the glowplug
Filament surface has roughened and turned white.
Filament coil has become distorted.
Foreign matter has adhered to filament or plug
body has corroded.
Engine tends to cut out when idling.
Starting qualities deteriorate.
•
•
•
•
•
•
•
•
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
14

STARTING THE ENGINE
Preparations
1Installing the glowplug
Install the washer on the
glowplug and screw carefully
into cylinder-head, making sure
that it is not cross-threaded
before tightening firmly. Washer
Glow plug
2Installing the propeller
There is 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. To prevent this from
happening even if the propeller itself should slip or
loosen, it is recommended to use the special Propeller
Locknut Set (optional extra) with the FS-40S.
Wrench
Tighten the propeller nut
firmlysothatcompression
is first felt around this
position(i.e. with blades
horizontall) when turning
the propeller in the
direction of arrow.
3Filling the fuel tank
Re-connect fuel line to
engine after tank is
filled.
Disconnect
fuel line from
the fuel inlet,
and connect
it to the
tubing from
the fuel
pump.
Do not let dirt or
dust enter fuel can.
Fuel (model
glow-plug
engine fuel)
Fuel pump
Use a fuel can filter
(e.g. O.S. Super Filter).
15

Close
Open
4 Opening and closing of the needle-valve
Turn needle-valve clockwise to close (for
leaner mixture).
Turn needle-valve counter-clockwise to
open (for richer mixture).
Starting
Turn the needle-valve in the direction
of arrow slowly, without forcing, until it
stops.
5 Setting the needle-valve
The position where the needle-valve
stops is the fully closed position. It may
be convenient to remember the position
of the mark or set-screw at this time.
Set-screw
Turn the needle-valve in the direction
of arrow from the closed position.
FS-26S (3 to 3-1/2 turns)
FS-40S (2-1/2 to 3 turns)
6Open the throttle fully
Fully closed position Fully opened position
Throttle
Open
Close
Fuel will flow from tank to
carburettor as propeller is
turned.
Close the air intake
by operating the
choke control.
Turn the propeller
four revolutions
while watching
fuel line.
Turn the propeller 3
to 4 turns counter-
clockwise smartly
by finger in the
direction of arrow.
Turn approx.
10 turns when the
engine is cold.
7 Priming
16

8 Hold model securely when starting
9 Setting the throttle
10 Heat glowplug
Starter
Assistant should hold
the model so that it
cannot move forward
when the engine starts.
Be careful not
to be hit by propeller!
Fully opened
position
Fully closed
position
Set at this Position.
Starting battery
Connect battery leads as shown
(polarity is immaterial.)
11 Apply electric starter
Assistant
Glowplug battery.
Place as far to the
rear as possible.
17

Check that the throttle is one-third open from the fully
closed position. Bring the starter into contact with the
spinner nut or spinner and depress the starter switch
for one or two seconds. Repeat if necessary. When
the engine fires, withdraw the starter immediately.
Attention: Never place your finger over the
carburettor intake when applying the starter. Such an
action will cause an excess quantity of fuel to be
drawn into the cylinder and result in hydraulic lock
that may damage the engine.
BEWARE of
the rotating
propeller.
12 Engine starts
In the interests of safety, keep your face and other parts of the
body away from the vicinity of the propeller.
Listen to the sound
carefully.
13 Needle-valve adjustment(1)
Slowly advance throttle to its
fully open position, then
gradually close the needle-
valve until the exhaust sound
changes pitch.
Close the needle-valve gradually until a
high-pitched exhaust note begins to be
superimposed on the lower-pitched
sound.
14 Disconnect battery leads
Disconnect the battery leads
from the engine with care so
that the plug clip does not touch
the rotating pro-peller.
If the engine stops when battery
leads are disconnected, close
the needle-valve a little (approx.
45˚) further, and restart the
engine.
18

20 ~ 30°
15 Needle-valve adjustment(2)
As the needle-valve is closed beyond the initial readjustment,
the rpm of the engine will be increased and a continuous high-
pitched exhaust note, only, will be heard.
Key to the needle-valve
adjustment.
(Turn 15-30˚ at a time.)
Turn the needle-valve 15-30˚ in the direction of arrow, and wait
momentarily for the change of r.p.m.
After the rpm of the engine increases, turn the needle-valve
another 10-15˚ and wait for the next change of r.p.m.
As the speed of the engine does not instantly change with
needle-valve readjustment, small movements, with pauses
between, are necessary to arrive at the optimum setting.
16 Needle-valve adjustment(Summary)
Practical best(optimum) needle-valve setting
Disconnect battery leads from
glowplug at about this point.
Maximum rpm setting("Lean").
"Rich" needle-valve
setting when starting
the engine.
E
n
g
i
n
e
s
t
o
p
s
R
e
v
o
l
u
t
i
o
n
s
s
t
a
r
t
t
t
o
d
e
c
r
e
a
s
e
.
t
o
d
e
The engine may stop if the battery leads
are disconnected from the glowplug while
the engine is running rich.
NOTE: The above sketch is for reference purposes only.
Actual needle positions may differ from those shown.
19