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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.

Summary of Contents for FS-26S

Page 1: ...ontained 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 ...

Page 2: ... SILENCER LINKAGE OF THROTTLE LEVER BEFORE STARTING FUEL AND 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...

Page 3: ...e 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 co...

Page 4: ...ead 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 fai...

Page 5: ...aring 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...

Page 6: ...he 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 in any way unless you are highly experienced in tuning propellers for specialized competition work such as pylon racing Take care that the glow plug clip or battery leads do n...

Page 7: ... 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 Warn...

Page 8: ...engines for model aircraft use and are the 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...

Page 9: ...e 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 su...

Page 10: ...e 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 loo...

Page 11: ... 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 BEFO...

Page 12: ...hrome 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 th...

Page 13: ...one 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 ...

Page 14: ... fuel is used the engine should be checked out to make sure that it is sufficiently run in to operate on that particular fuel without overheating Do not use fuels containing less than 18 lubricant ADVICE ON SELECTION OF FUEL GLOWPLUG PROPELLER A B 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 stor...

Page 15: ...drpm 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...

Page 16: ...d 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 firmly so that compression is first felt around this position i e with blades horizontall when turning the propeller in the direction of arrow 3 Filling the fuel tank Re connect fuel line to en...

Page 17: ...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 6 Open 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 prop...

Page 18: ...o 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 ...

Page 19: ...ropeller 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 b...

Page 20: ... 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 Engine stops R e v o ...

Page 21: ...eedle valve setting has been established see Needle valve adjustment Summary the procedure for starting is simplified as follows 1 Open the needle valve one half turn 180 from the optimum setting 2 Open the throttle fully place your finger over the carburettor intake and rotate the propeller through two revolutions to prime the engine 3 Set the throttle one third open from the fully closed positio...

Page 22: ... aid of the finest modern precisionmachineryandfromthebestandmostsuitable materials only a very short and simple running in procedure is required and can be carried out with the engine installed in the model The process is as follows 1 Start the engine and with the throttle fully open open the needle valve an extra half turn 180 from the optimum setting This will produce a rich mixture that will r...

Page 23: ...ine to be varied proportionally from idling speed to full power The carburettor of your engine has been factory set for the approximate best results and no adjustment except to the needle valve should be required provided that the fuel tank is correctly located as previously described After the engine has been run in check the operation of the throttle according to the following chart Re adjust th...

Page 24: ...he engine stop Apply full throttle Does the engine regain full power immediately OK Refer to the CARBURETTOR AIR BLEED ADJUSTMENT section on page 24 Re set the idling position at a little higher r p m Set the throttle opening by means of the throttle trim on the transmitter so that the lowest practical speed without risk of the engine stopping is obtained The position where the lowest possible r p...

Page 25: ...again Stop the engine Stop the engine Note Stop engine by pinching fuel line Do not touch needle valve Open air bleed screw Half turn at a time Close air bleed screw Half turn at a time Pre Flight Check Repeat the procedure while opening and closing the throttle until the best result is obtained Attention Do not leave the glowplug connected to the battery while adjusting the carburettor throttle T...

Page 26: ...e referring to 7 Priming Sluggish rotation Glowplug battery discharged Glowplug element is burned out Something wrong with battery leads Engine flooded due to excessive priming Insufficient priming Engine fails to fire TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START Four key points For quick reliable starting the following four conditions are required 1 Good compression 2 Adequate glow at glowplug...

Page 27: ...ocedure referring to 7 Priming Close needle valve half turn 180 and wait for several minutes then re start Priming is not necessary Make sure that tank is filled with fuel Check that there is not something wrong with fuel tubing kinked or split Check that carburettor is not clogged with dirt Close the needle valve a little Change fuel or glowplug Incorrect heating of glowplug Over priming Sluggish...

Page 28: ...mm Wrench 5mm Note Valve clearances of all O S four stroke cycle engines must be checked and reset ONLY WHEN THE ENGINE IS COLD Procedure is as follows Remove the cover from the rocker box on top of the cylinderhead using the correct size Allen hex key 1 1 Turn the propeller counter clockwise until compression is first felt then turn it futher quarter turn At this point both valves should be close...

Page 29: ...adjust the clearance if the engine runs satisfactorily Fig 1 0 04mm Feeler Gauge Rocker Arm Valve 2 If a clearance is found to be outside either of these limits it should be reset as follows Carefully loosen the locknut on rocker arm 1 4 1 2 turn with 5mm wrench Fig 2 1 2 Wrench Slacken approx 1 4 to 1 2 turn Turn adjusting screw approx 1 2 turn counter clockwise to open gap using appropriate tool...

Page 30: ...ad Fig 5 Tighten Locknut Remove 0 04mm feeler rotate prop through two revolutions and recheck gap 5 If clearance is correct loosen the locknut on the other rocker arm and repeat steps 1 to 5 above Finally replace rocker box cover 6 Remember Excessive valve clearance will cause loss of power due to valve s not opening sufficiently On the other hand a total loss of clearance may cause difficult star...

Page 31: ...ngine at the conclusion of a flying session it may cause corrosion The best practice is to disconnect the fuel line from the carburettor while the engine is running Remaining fuel in the tank should also be drained off 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 bec...

Page 32: ...41 cc 0 269 cu in 18 5mm 0 728 in 16 4mm 0 648 in 2 200 12 000 r p m 0 41 bhp 11 000 r p m 268g 9 45 oz FS 26S FS 40S FS 26S FS 40S THREE VIEW DRAWING Dimension mm Specification Displacement Bore Stroke Practical R P M Power output Weight Specification Displacement Bore Stroke Practical R P M Power output Weight 31 ...

Page 33: ...2 6X7 a s d f y t r e w q 7 4 3 2 1 5 4 5 3 5 2 4 1 4 2 3 2 3 1 5 6 1 2 2 5 1 i u o p 8 1 y 1 g FS 26S ENGINE EXPLODED VIEW Type of screw C Cap Screw B Binding Head Screw M Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw 32 ...

Page 34: ...tion Code No Screw Set Rocker Cover Rocker Support Assembly Rocker Support Rocker Arm Retainer 2pcs Rocker Arm Assembly 1pair Rocker Arm 1pc Tappet Adjusting Screw Valve Assembly 1pair Intake Valve 1pc Valve Spring 1pc Valve Spring Seat 1pc Valve Spring Retainer 2ps Cylinder Head W Gasket Cylinder Head W Gasket and Valve Assembly Carburetor Complete Carburetor Retaining Screw 2pcs Gasket Set Pisto...

Page 35: ... C M2 6X12 C M3X8 C M2 6X7 y t r e w q 7 4 3 2 1 5 4 5 3 5 2 4 1 4 2 3 2 3 1 5 6 5 1 i u 8 1 FS 40S ENGINE EXPLODED VIEW Type of screw C Cap Screw B Binding Head Screw M Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw 34 ...

Page 36: ... Push Rod Cover O Ring 2pcs Cam Follower 2pcs Crankshaft Ball Bearing Front Drive Hub Propeller Washer Propellern Nut Silencer Assembly Silencer Exhaust Header Pipe Glow Plug Type F 4 5225 010 4 5225 000 2 3210 007 2 3209 003 4 5208 010 4 5231 000 4 5264 000 2 4881 824 4 5266 112 4 5266 102 4 5266 010 i 4 5201 110 u 4 5262 010 4 5231 100 y 4 5201 040 t r 2 2630 002 e w q 4 5202 010 4 5771 000 4 52...

Page 37: ...Fillister head Screw F Flat Head Screw N Round Head Screw S Set Screw Specifications are subject to alteration for improvement without notice Description Code No Throttle Lever Assembly Throttle Lever Retaining Screw Carburetor Rotor Carburetor Body Carburetor Retaining Screw 3pcs Throttle Stop Screw Needle valve Assembly Needle Set screw Nozzle Assembly Ratchet Spring Nozzle Retaining Screw 2pcs ...

Page 38: ... 28 23024008 For 40S 45810100 For 40S 1010A 72108300 1010B 72108310 72200060 PARTS ACCESSORIES Radial Mount Set O S Glow Plug TYPE F Flexible Exhaust Pipes Spinner Nut NON BUBBLE Weight Propeller Locknut Set Valve Adjusting Tool Kit Super Filter L Long Socket Wrench With Plug Grip 37 ...

Page 39: ...MEMO 38 ...

Page 40: ...ghts reserved Printed in Japan U N EQUALLED QUALITY PRECISION PERFORMAN C E ESTABLISHING THE STANDARDS OF EXCELLENC E 110101 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 ...

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