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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.

WARNINGS

These  cover  events  which  might  involve  serious  (in 
extreme circumstances, even fatal ) injury.

NOTES

These cover the many other possibilities, generally less 
obvious  sources  of  danger,  but  which,  under  certain 
circumstances, may also cause damage or injury.

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

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 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 an 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.

Never  operate  your  engine  in  an  enclosed  space.  Model 
engines,  like  automobile  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.

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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'  recommendations,  using  appropriate 
screws and locknuts.

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.

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. A safety locknut assembly is provided.  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.

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 in any way, unless you are highly experienced in tuning 
propellers for specialized competition work such as pylon-racing.

Use an electric starter for this engine. The wearing of safety glasses is also strongly recommended.

Summary of Contents for FS-120S-E

Page 1: ...he aircraft radio control equipment etc are accessible for checking at the same time 1 14 15 SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE INTRODUCTION INSTALLING THE GLOWPLUG BASIC ENGINE PARTS RELOCATION OF CARBURETTOR CONTROLS CHOKE VALVE FUEL TANK INSTALLATION EXHAUST HEADER PIPE AND SILENCER THROTTLE LINKAGE NEEDLE VALVE EXTENSION PROPELLERS PROPELLER AND SPINNER ATTACHMENT FUEL GLOW...

Page 2: ...your engine in an enclosed space Model engines like automobile 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 3 NOTES This engine was designed for model aircra...

Page 3: ...aring 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 cas...

Page 4: ...ng 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 Make sure that the mounting beams are parallel and that their top surfaces are in the same plane How to fasten the mounting screws Hardwood mounting beams O S radial motor mount cast aluminum Tighten second nut firmly down onto first...

Page 5: ...er joints which may loosen when they are hot use a thick folded cloth for protection 9 The choice of propeller depends on the design and weight of the aircraft and on the type of flying in which you will be engaged Determine the best size and type after practical experimentation As a starting point refer to the props listed in the accompanying table Slightly larger or even slightly smaller props t...

Page 6: ... Use a good quality well balanced spinner enclosing the propeller boss Make sure that it is of precision made and sturdy construction so that the spinner shell cannot loosen when the starter is used Make sure the spinner notches do not interfere the propeller If they do cut the notches to clear off 11 GLOWPLUGS The role of the glowplug Glowplug life Particularly in the case of very high performanc...

Page 7: ...being insufficiently charged 1 2 3 4 5 6 Check these conditions and instead of pressing the starter button after applying the starter have the starter spinning before applying it to the engine to give it a running start When the engine starts slowly open the throttle leaving the needle valve at its rich starting setting to promote cool running conditions However if the engine slows down because th...

Page 8: ... to fine tolerances and from the finest quality materials a relatively brief running in period is sufficient and can be completed with the engine installed in the aircraft The recommended procedure is as follows 15 Start the engine open the throttle fully and set the needle valve slightly rich 30 45 from the highest r p m setting Close the throttle to the idle position Allow the engine to idle for...

Page 9: ...eeler gauge 0 04mm Valve clearances are correctly set before any O S engine leaves the factory and in normal use will seldom require abjustment However if after a very considerable amount of running time has been amassed a loss of power is detected or if the engine has been disassembled for repair these clearances should be checked and reset as necessary For this purpose a valve adjusting kit comp...

Page 10: ...il through the plug hole and carburetor intake again rotating the shaft to distribute the protective oil to all working parts Gasoline thinner kerosene and light machine oil cause swelling and deterioration of plastic parts O rings and fuel tubing Use methanol for cleaning these engines Avoid unnecessary dismantling of your engine 3 4 5 6 Do not leave raw fuel in the engine at the conclusion of a ...

Page 11: ...1 28 2 29 30 31 32 32 1 33 71615009 45526400 45526300 45526200 45526100 45526010 45525011 45525001 Description Code No No Description Code No No Screw Set Rocker Cover Rocker Support Assembly Rocker Support Rocker Arm Retainer 2pcs Rocker Arm Assembly 1pair Rocker Arm 1pc Tappet Adjusting Screw Intake Valve Assembly 1pair Intake Valve 1pc Valve Spring 1pc Valve Spring Retainer 1pc Split Cotter 2ps...

Page 12: ...Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw Description Code No No Needle Valve Assembly Needle O Ring 2pcs Set Screw Needle Valve Holder Assembly Ratchet Spring Carburetor Body Rotor Guide Screw Fuel Inlet Mixture Control Valve Assembly Carburetor Retaining Screw 2pcs Throttle Lever Assembly Set Screw Carburetor Rotor O Ring 2pcs Rotor Spring Carburetor Rubber Gaske...

Page 13: ...served Printed in Japan TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan URL http www os engines co jp U N E Q U A LLED QUALITY PRECISION PERFOR M A N C E E S T A BLISHING THE STANDARDS OF EXCELLE N C E 60090510 061103 ...

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