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INTRODUCTION

THE MAX-10LA,15LA,25LA have been developed to 
meet the requirements of  beginners and sport 
flyers.
Of modern design and having a separate needle-
valve unit mounted at the rear, where manual 
adjustment is safely remote from the rotating 
propeller, they offer the advantages of reliability 
and easy handling, at lower cost. Like all O.S. 
engines they are built to standards of engineering 
excellence that have evolved through more than 60 
years' experience in the design and production of 
model internal-combustion engines. Advanced 
modern precision machinery, top quality materials 
and the efforts of highly skilled craftsmen and 
technicians are combined  to ensure a continuation 
of the levels of performance, durability and 
reliability for which O.S. is world famous. 

The 'midnight blue' external finish may be 
decolorized by very high surface temperature or 
by certain solvents. Such decolorization does not 
affect engine perfor-mance, however.

Cylinder head

Carburettor 

Silicone Tubing

Crankshaft

Propeller nut

Propeller washer

Drive Hub

Crankcase

Needle valve

Cover Plate

Fuel outlet

Fuel inlet

Glowplug

Connect the short length of fuel tubing supplied 
securely between the fuel outlet and the fuel inlet. In 
the event of the tubing becoming damaged, it should 
be replaced with a suitable length of best quality 5mm 
ODX2mm ID silicone tubing. Use similar material to 
connect the fuel inlet nipple to the fuel tank.

7

Summary of Contents for MAX-10LA

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: ...E RUNNING IN Breaking in TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START CARE AND MAINTENANCE OPTIONAL PARTS ACCESSORIES 10LA ENGINE EXPLODED VIEW PARTS LIST 15 25LA ENGINE EXPLODED VIEW PARTS LIST CARBURETTOR EXPLODED VIEW PARTS LIST 10LA THREE VIEW DRAWING 2 6 7 8 9 10 12 12 14 14 22 23 23 24 26 27 25 28 29 30 31 CARBURETTOR 15 25LA CARBURETTOR AIR BLEED ADJUSTMENT 32 33 34 35 15 25LA THREE VIEW...

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: ... 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 f...

Page 5: ...hearing 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 direction of flight Firmly tighten the propeller nut using the correct size wrench If you remove the glowplug from the engine and c...

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: ...ighly skilled craftsmen and technicians are combined to ensure a continuation of the levels of performance durability and reliability for which O S is world famous The midnight blue external finish may be decolorized by very high surface temperature or by certain solvents Such decolorization does not affect engine perfor mance however Cylinder head Carburettor Silicone Tubing Crankshaft Propeller ...

Page 9: ...T 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 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...

Page 10: ...e rotated to any desired position in the following manner 1 Loosen the locknut and assembly screw 2 Set the exhaust outlet at the required position by rotating the rear part of the silencer 3 Re tighten the assembly screw followed by the locknut The standard silencer is quite effective but reduces power to some degree INSTALLATION OF SILENCER Assembly screw Cone baffle Turn to requlred position Ex...

Page 11: ...olt 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 bri...

Page 12: ...rent from the battery to the glowplug Basically two leads with clips are required but for greater convenience twin leads with special glowplug connectors as shown on the right are commercially available 7 Fuel tank For installation in the model a 70cc 2 5oz for 10LA a 100cc 3 5oz for 15LA a 150cc 5oz for 25LA tank is suggested 8 Fuel bottle or pump For filling the fuel tank a simple polyethylene s...

Page 13: ...as shown left Fuel Use a good quality commercial fuel or one of the blends shown in the table Fuel A is suitable for running in and ordinaryuse Fuel B isforusewhenmorepowerisrequired 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 high...

Page 14: ...er practical experiment Trainer Sport LA Series 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 Running in Reminder GLOWPLUG An O S A3 glowplug is fitted to the engine Other recommended O S plugs are Nos 8 and A5 Carefully fit plug finger tight before final tightening with the correct size plug wrench The role of...

Page 15: ...INE Preparations 1 Installing the glowplug Install washer on the glowplug and insert carefully into cylinder head making sure that it is not crossthreaded before tightening firmly Glow plug Washer 2 Installing the propeller First install the propeller on the engine by tightening the prop nut or spinner nut lightly and make sure of the position where compression is felt turning the propeller counte...

Page 16: ... after compression is felt Compression is first felt around this posi tion when turning the propeller slowly Dribble a few drops of fuel around the glowplug and look for air bubbles If leakage is detected remove the glowplug carefully wipe threads re insert and tighten firmly Do not allow fuel to overflow into silencer when refuelling otherwise engine may become flooded and difficult to start Re c...

Page 17: ...ed Place your finger over the carburettor to choke intake Turn the propeller two revolutions while watching fuel line 5 Opening and closing of the needle valve 6 Setting the needle valve Turn needle valve clockwise to close for leaner mixture Turn needle valve counter clockwise to open for richer mixture The position where the needle valve stops is the fully closed position It may be convenient to...

Page 18: ...ing started for the first time turn the propeller two revolutions after fuel reaches the fuel inlet as described above However when re starting the engine immediately after a run one revolution or even no priming at all may be required The engine s requirements will be quickly learned with experience Priming quantity 9 Turn the propeller 3 to 4 turns counter clockwise smartly by finger in the dire...

Page 19: ...hat it cannot move forward when the engine starts Be careful not to be hit by propeller Glowplug battery Place as far to the rear as possible Fully opened position Fully closed position Set at this Position 1 3 2 3 Starting battery Connect battery leads as shown polarity is immaterial 13 Apply electric starter Assistant 18 ...

Page 20: ...nto the cylinder and result in hydraulic lock that may damage the engine BEWARE of the rotating propeller 14 Engine starts If the engine does not start refer to the TROUBLE SHOOTING CHART on page 26 27 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 15 Needle valve adjustment 1 Slowly advance throttle to it...

Page 21: ...heard Key to the needle valve adjustment Turn 10 15 at a time Turn the needle valve 10 15 in the direction of arrow and wait momentarily for the change of r p m After the rpm of the engine is increased 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 ...

Page 22: ...ses only Actual needle positions may differ from those shown On starting from cold with the needle valve set at the rich starting position Take note of this position of the needle valve This will produce the practical best i e optimum rpm setting lower than maximum rpm A light grey exhaust emission may be observed Now re open needle valve 20 30 maximum rpm is reached and will fall off or engine wi...

Page 23: ...rts re open the throttle and re adjust the needle valve to the optimum setting 19 How to stop the engine Close the throttle to reduce to the lowest possible r p m Close With the transmitter throttle trim lever fully retarded adjust the throttle servo linkage so that the throttle rotor is fully closed i e engine stopped when the stick is fully retarded Subsequent starting procedure 18 Note When re ...

Page 24: ...y surroundings 2 Now fly the model with the needle valve re set 20 30 degrees open from the optimum setting i e 40 60 from the highest rpm setting 3 Close the needle valve very slightly on successive flights so that the engine is running on its optimum needle setting at the fifth or sixth flight RUNNING IN Breaking in These engines are equipped with a throttle type car burettor which provides a wi...

Page 25: ...he engine stop Apply full throttle Does the engine regain full power immediately OK Refer to the CARBURETTOR AIR BLEED ADJUSTMENT section on page 25 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 26: ...gain Stop the engine Stop the engine Note Stop engine by pinching fuel delivery tube 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 th...

Page 27: ...ocedure referring to 8 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 gl...

Page 28: ... Repeat priming procedure referring to 8 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 Ove...

Page 29: ...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 30: ...5LA 23024008 for 25LA EXHAUST ADAPTORS SPINNER NUT LONG PROPELLER NUT SET NON BUBBLE WEIGHT SUPER FILTER L SILENCER EXTENSION ADAPTORS GLOW PLUG LONG SOCKET WRENCH WITH PLUG GRIP 73101000 for 25LA 72403050 71521000 71605300 71531000 4 1 M5 20824005 for 10 15LA A3 21125502 for 10 15LA No 8 71608001 72200080 NEEDLE VALVE EXTENSION CABLE SET 29 ...

Page 31: ...Type of screw C Cap Screw M Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw EXPLODED VIEW MAX 10LA 1 2 3 3 1 4 5 6 7 8 9 0 1 2 q M M2 6X7 S 3X3 M M2 6X10 30 ...

Page 32: ...her Crankcase Crankshaft Cover Plate Needle O Ring Set Screw Head Gasket Screw Set Glow Plug A3 871 Silencer Pressure Fitting Assembly Screw Retaining Screw N M2 6X25 2pcs Description Code No 2 1004 000 2 1003 000 2 1081 000 2 7881 120 2 0810 007 2 1109 005 2 1758 000 2 1620 006 2 1001 000 2 1002 000 2 1007 000 2 1781 970 2 4981 837 2 6381 501 2 1014 000 2 1013 000 7 1605 300 2 1225 000 2 2681 957...

Page 33: ... C Cap Screw M Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw w q 0 5 4 3 1 2 5 1 5 2 3 5 4 2 1 N M3X12 25LA N M3 5X5 B M2 6X8 S 3X3 M M2 6X10 15LA 9 8 7 6 EXPLODED VIEW MAX 15LA 25LA 32 ...

Page 34: ...4081970 22564000 22563000 22325020 22625404 1 2 3 4 5 1 5 2 6 7 8 9 0 1 2 3 4 5 q w Cylinder Head Cylinder Piston Assembly Piston Pin Connecting Rod Carburettor Complete 10G Carburettor Complete 20H Carburettor Rubber Gasket Carburettor Retaining Screw 2pcs Propeller Nut Propeller Washer Drive Hub Thrust Washer Crankcase Crankshaft Cover Plate Assembly Cover Plate Ratchet Spring Needle O Ring Set ...

Page 35: ...783100 21783300 21015001 Throttle Lever Assembly Throttle Lever Fixing Screw Carburettor Rotor Air bleed Screw Carburettor Body Throttle Stop Screw Carburettor Gasket Carburettor Retaining Screw Description Code No 10G 20H 22081408 22081313 23081706 1 1 1 2 3 4 5 6 7 2 1081 400 2 4081 300 2 1081 200 2 1081 100 2 1081 300 2 7881 120 Throttle Lever Assembly Throttle Lever Fixing Screw Carburettor Ro...

Page 36: ...cal R P M Power output Weight 1 76 cc 0 107 cu in 13 44mm 0 529 in 12 4mm 0 488 in 2 500 18 000 r p m 0 27 bhp 17 000 r p m 112g 3 95 oz 10LA SPECIFICATIONS Dimensions mm 23 38 6 11 7 44 3 27 5 2 ø2 8 23 5 20 62 15 9 23 2 M5x0 8 4 ø3 3 33 2 11 31 4 38 7 19 2 35 ...

Page 37: ... bhp 15 000 r p m 197g 6 94 oz 25LA SPECIFICATIONS Displacement Bore Stroke Practical R P M Power output Weight 2 49 cc 0 1517 cu in 15 2mm 0 598 in 13 7mm 0 539 in 2 500 18 000 r p m 0 41 bhp 17 000 r p m 138g 4 87 oz 15LA SPECIFICATIONS 15LA Dimensions mm UNF1 4 28 M5 39 30 8 14 14 4 46 5 39 5 36 33 32 27 5 30 5 25 8 60 48 5 74 5 61 22 20 29 24 8 44 40 67 5 56 5 36 ...

Page 38: ...g Co Ltd All rights 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 ...

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