O.S. engine MAX-15, MAX-40, MAX-46, MAX-25, 15LA-S Owner's Manual

...

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.

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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.

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CONTENTS

SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE

INTRODUCTION

INSTALLATION OF THE ENGINE

INSTALLATION OF SILENCER

NEEDLE-VALVE LOCATION

BEFORE STARTING

PLUMBING AND FUEL TANK POSITION

ADVICE ON SELECTION OF FUEL, GLOW PLUG & PROPELLER

ST AR TING THE ENGINE

RUNNING-IN (Breaking-in)

TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START

CARE AND MAINTENANCE

ENGINE EXPLODED VIEW & PARTS LIST

THREE VIEW DRAWING

OPTIONAL PARTS & ACCESSORIES

2~6

28~29

Remember that your engine is not a "toy", but a highly efficient internalcombustion 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.

WARNINGS

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.

Never operate your engine in an enclosed space. Model engines, like automobile engines, exhaust deadly carbonmonoxide. 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 anything else which might ignite it. Do not smoke or allow anyone else to smoke, near to it.

•

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.

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 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.

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 fit 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 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 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.

•

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 glowplugignition 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!

INTRODUCTION

The "LA-S Series" engines are designed for control line models. They have broad power characteristics which are suitable for both trainer models and stunt models. A separate needle-valve is mounted at the rear, where manual adjustment is safely away from the rotating propeller.

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

Venturi

Silicone Tube

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 tube 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.

Length

15LA-S 25LA-S 40/46LA-S

52mm

56mm

66mm

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 3mm steel screw

Spring washer or lock washer

Hardwood such as cherry or maple.

Spring washer

3mm steel Allen screw

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 seat 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 that the mounting beams are parallel and that their top surfaces are in the same plane.

At least 12mm(1/2")

3mm steel nuts

NEEDLE-VALVE EXTENSION

The needle-valve supplied with these engines 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 a commercially available rod to the required length, bend one end to an L shape, insert it into needle's center hole and secure it by tightening the set-screw in the needle-valve knob with 1.5mm. Allen key.

The angled exhaust of the silencer can be 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

Exhaust outlet

Locknut

Exhaust pressure nipple

Reminder!

As delivered from the factory, the MAX-40LA & 46LA have the needle-valve assembly installed vertically. However, if more convenient for a particular installation, the needle-valve may be reinstalled horizontally. The procedure for relocating the needle-valve is as follows:

NEEDLE-VALVE LOCATION

Finally, secure the complete assembly to rear cover plate as before.

As self-tapping screws are used for unit attachment, screw them in carefully so that screw threads match those of the unit body precisely.

Note:

Remove the two cover-plate screws which secure the needle-valve assembly bracket, then carefully remove the two screws by which the needle-valve unit is attached to the bracket.

Rotate the needle-valve unit through 90˚ and reattach it to the bracket in the required position.

Vertical position

Horizontal position

Cover plate fitting holes

Needle Valve unit

Needle Valve unit attachment screws

Needle-Valve Assembly Bracket

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. A3 glowplug is installed in the engine.

3 Propeller

Suggested size is 8 X4 (15LA-S), 9 X6 (25LA-S),11X5 (40LA-S), or 11X6 (46LA-S).

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 the 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)

5 Plug wrench

Used for tightening glowplug. The O.S. long plug wrench is available as an optional accessory.

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 convenience, twin leads with special glowplug connectors, as shown on the right, are commercially available.

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.

9 Fuel can filter

Fit a filter to the outlet tube of your refuelling container to prevent entry of foreign matter into the fuel tank. (R/C clunk tank installation)

For tightening glowplug

Fuel bulb

Battery leads

Manual

Electric

Fuel pumps

Fuel Can Filter

12V Battery

Starter

10 Silicone tubing

This is required for the connection between the fuel tank and engine.

11 Electric starter and starter battery

An electric starter is recommended for starting.

Never touch the nichrome wire while the battery is connected.

7 Fuel tank

For installation in the model, a 40cc(1oz.) for 15LA-S, a 60cc(2oz.) for 25LA-S, a 120cc(4oz.)-140cc(5oz.) for

40.46LA-S, is suggested.

Make sure that there are no kinks or folds in the plumbing.

Silicone tubing

Use knife or razor blade.

Do not use wire cutters or pliers

Note: When cutting silicone tubing......

*If you should need to clean out silicone tubes, use methanol or

glow-fuel, not gasoline.

Note: Control line models tend to receive more abrupt changes of attitude than R/C models,which results in air bubbles being drawn from the fuel tank. Pay careful attention to the plumbing and fuel tank position.

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.

Fuel

Use a good quality commercial fuel or one of the blends shown in the table. Fuel "A" is suitable for 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" than castor-oil. If, therefore, a synthetic lubricant 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. If a more powerful 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

5~8

(example)

15LA-S 25LA-S 40/46LA-S

11.5mm 12mm 13mm

PLUMBING AND FUEL TANK POSITION

Measurement A (height from the bottom surface of the mounting lug to the center of the spray bar)

Metal control line fuel tank installation

R/C clunk tank installation

Make sure that the center of the spray bar and tank are on the same line.

75% 20%

65% 20% 10%

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!

8✕4 9

✕6

✕5

✕6

15LA-S 25LA-S 40LA-S 46LA-S

✕4

✕6,10✕5

✕5

✕6

7,12✕5~6

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.

Aerobatic & 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.

Running-in

Reminder!

GLOWPLUG

An O.S. A3 glowplug is installed in 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 the glowplug

With a glowplug engine, ignition is initiated by the application of a 1.5-volt power source. When the battery is disconnected, the heat retained within the combustion chamber remains sufficient to keep the plug filament glowing, thereby continuing to keep the engine running. Ignition timing is 'automatic' : under reduced load, allowing higher rpm, the plug becomes hotter and, appropriately, fires the fuel/air charge earlier; conversely, at reduced rpm, the plug become cooler and ignition is retarded.

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.

•

STARTING THE ENGINE

Preparations

1 Installing the glowplug

Install the washer on the glowplug and screw carefully into cylinder-head, making sure that it is not crossthreaded before tightening firmly.

Glow plug

Washer

2 Installing the propeller

First, mount 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 counter-clockwise slowly. Then tighten firmly as explained below.

Glowplug life

Particularly in the case of very high performance engines,

glowplugs must be regarded as expendable

For accurately centering the starter's rubber drive insert, use an O.S. solid alloy spinner-nut. (Available as an optional extra part).

Alternatively, a spinner assembly, enclosing the propeller boss, may be used, but make sure that it is of sturdy construction and that the spinner shell does not loosen when the starter is used.

Wrench

Warning: When using a spinner assembly, make sure that the notches in the spinner shell are large enough to clear the propeller blades and so do not cut into and weaken the blade roots.

Tighten the spinner nut firmly so that compression is first felt as indicated (i.e. with blades horizontal) when turning the propeller in the direction of arrow.

3 Filling the fuel tank

Do not allow fuel to overflow into silencer when refuelling, otherwise engine may become flooded and difficult to start.

Fuel pump

Use a fuel can filter (e.g. O.S. Super Filter).

Re-connect delivery tube to engine after tank is filled.

Disconnect delivery tube 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)

1 2

Close Open

Open

Open the needle-valve 3 turns (for 15LA-S), 1 turns(for 25,40,46LA-S) in the direction of arrow from the closed position.

4 Opening and closing of the needle-valve

5 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 remember the position of the mark or set-screw at this time.

Fuel inlet

Fuel Tube

Fuel will flow from tank to venturi as propeller is turned.

Place your finger over the venturi to choke intake.

Turn the propeller two revolutions while watching the fuel line.

6 Priming

Hold model securely when starting

Starter

Assistant

Assistant should hold the model so that 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.

8 Heat glowplug

Starting battery

Connect battery leads as shown (polarity is immaterial.)

Turn the engine for 3 to 4 seconds by an electric starter without connecting glowplug battery.

9 Apply electric starter

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.

Engine starts

If the engine does not start, refer to the TROUBLE SHOOTING CHART .

In the interests of safety, keep your face and other parts of the body away from the vicinity of the propeller.

Warning! Since a control line engine is started with the

throttle fully opened and reaches full rpm right after starting, be sure to hold the model securely.

Listen to the sound carefully.

Needle-valve adjustment(1)

Then gradually close the needle-valve until the exhaust sound changes from an irregular pitch (four-cycle) to a steady pitch (two-cycle).

Close the needlevalve gradually until the engine sound is changing from a four-cycle into a twocycle in pitch.

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.

Needle-valve adjustment(2)

As the needle-valve is closed beyond the initial readjustment, the r.p.m. of the engine will be increased and a continuous high-pitched exhaust note, only, will be heard.

Key to the needle-valve adjustment. (Turn 20-30˚ at a time.)

Turn the needle-valve 20-30˚ in the direction of arrow, and wait momentarily for the change of r.p.m. After the r.p.m. of the engine increases, turn the needle-valve another 20-30˚ 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.

IMPORTANT NOTE

When fine-tuning the needle-valve to reach peak performance, take care not to run the engine too lean and cause it to overheat. Be sure to observe the simple running-in procedures described on Page 20.

Needle-valve adjustment(Summary)

Practical best(optimum) needle-valve setting

Exhaust note starts to change.

Disconnect battery leads from glowplug at about this point.

Clear, high-pitched two-stroke exhaust note

Maximum rpm setting("Lean").

"Rich" needle-valve setting when starting the engine.

The engine may stop if the battery leads are disconnected from the glowplug while the engine is running rich.

Note: Although this is a two-stroke engine it fires like a four-stroke at these rich needle-valve settings-i.e. ignition of the fuel charge takes place at every fourth stroke of the piston instead of at every second stroke.

20~30˚

Intermittent, high-pitched two-stroke note superimposed on low "four-stroke" sound.

NOTE: The above sketch is for reference purposes 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 will stop) if needle -valve is closed any further. Exhaust gas will be very light.

Finally:

exhaust note is now a steady high-pitched sound,rising higher in pitch as needle-valve is closed and

increase. The grey smoke will be lighter. (However, make sure that engine is fully run in.)

Further needle-valve closure:

an intermittent high-pitched two-stroke note will be superimposed on the low-pitched "four-stroke" note. Exhaust smoke will be less dense and grey in colour.

As the needle-valve is closed and the r.p.m. increases:

a good deal of white smoke is emitted, accompanied by a relatively low-pitched "four-stroke" exhaust note.

Once the optimum needle-valve setting has been established (see "Needle-valve adjustmentSummary") the procedure for starting is simplified as follows:

1) Open the needle-valve one half-turn (180˚) from the optimum setting.

2) Energize the glowplug and apply the starter.

When the engine starts, re-adjust the needle-valve

to the optimum setting.

Subsequent starting procedure

Note: When re-starting the engine on the same day, provided that atmospheric conditions have not changed significantly, it may be practicable to re-start the engine on its optimum (running) setting. Also, if the engine is being re-started immediately after a run (i.e.hot), priming should not be necessary.

How to stop the engine

To cut off the fuel supply, pinch the fuel delivery tube to the venturi.

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 stresses. However, because 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.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 result in cooler running. Allow the engine to run out a full tank on the ground. (Avoid dusty surroundings.)

2) Now fly the model with the needle-valve re-set 2030 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")

Symptom

Factor

Cause

Corrective action

Recharge the electric starter battery.

Recharge lead-acid cell or replace dry battery. (Note: An unused, or almost unused, dry battery may sometimes be of insufficient capacity if it is "old stock".) Replace glowplug. Check that applied voltage is not too high.

Check glowplug heating using other leads. Close needle-valve fully and remove glowplug, then flip propeller to pump

out excess fuel. (Invert engine, if possible, while pumping out excess). Re-start engine. (Priming is not necessary at this time.)

Repeat priming procedure referring to 6 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.

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....

.....

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. 3 Correct mixture. 4 Sufficient electric starter rotating speed.

If the engine fails to start, or does not keep running after being started, check symptoms against the following chart and take necessary corrective action. Note: The most common causes of trouble are marked with three asterisks, the less common problems with one or two asterisks.

Symptom

Factor

Cause

Corrective action

2 3

3 3

3 2

Voltage too high or too low. Re-check and readjust referring to "BEFORE STARTING" paragraph 4.

Continue flipping propeller. If engine does not start after more than 10 flips, disconnect battery from glowplug and leave for a few minutes, then reenergize plug and flip prop again. If engine still does not start, remove glowplug and pump out excess fuel by flipping prop quickly.

Then re-start. (Priming is not necessary.) Recharge the electric starter battery.

Recharge lead-acid cell or replace dry battery. (Note: An unused, or almost unused, dry battery may sometimes be of insufficient capacity if it is "old stock".)

Repeat priming procedure referring to 6 Priming.

Close needle-valve half turn (180˚) and wait for several minutes then restart.(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 rotation.

Glowplug battery discharged.

Insufficient priming.

Mixture too rich.

Fuel not reaching the engine.

Mixture too rich.

Mismatch of glow plug and fuel.

Engine fires intermittently but does not run.

Engine fires once or twice, then fails to fire.

Engine starts but revolutions decrease and engine eventually stops.

Engine starts, then revolutions increase and engine cuts out.

Engine stops when battery leads are disconnected after starting.

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CARE AND MAINTENANCE

To ensure that you obtain long life and peak performance from your engine, observe the following.

Avoid running the engine under dusty conditions. If necessary, lay a sheet of plywood or hard-board in front and under the nose of the model when starting the engine.

Foreign matter in the fuel can cause the venturi jet to be partially clogged.

Therefore:

rinse out the fuel tank with methanol or fuel before installing it.

fit a fuel filter to the fuel delivery tube between tank and venturi.

fit a fuel filter to the outlet of your squeeze bottle, or to the pump inlet if you use a manual or electric

pump. do not leave your fuel container open needlessly. check filters periodically and clean them when

necessary.

•

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 venturi 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 become blackened.

If the engine is not in use 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 light machine-oil through the plug hole and carburettor 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 parts.

Avoid unnecessary dismantling of your engine.

-3

-5

-4

-2

-1

N.+M3X12(25LA-S)

M3.5

B.M2.6X8

S.3X3

M.M2.6X10(15LA-S)

EXPLODED VIEW

(MAX-15/25LA-S)

Type of screw C…Cap Screw M…Oval Fillister-Head Screw

F…Flat Head Screw N…Round Head Screw S…Set Screw

✽

ENGINE PARTS LIST

(MAX-15/25LA-S)

Specifications are subject to alteration for improvement without notice.

15LA-S

25LA-S

-1

-2

-3

-4

-5

22563000

24081970

22557100

22557000

22564000

22302000

22551000

22020001

22558000

24009000

23210007

21381980

22405013

22606009

22553000

22554000

71605300

21754000 21753000 21706000 21205040 21712010 21381970 20810007 21109005 21758000 21620006 21751000 21752000 21757000 21757100

21781970

21714100 21713000

21225000 22681957 22325300 21125409

22325020 22681957 22325310 22625404

22312000

26711305

24981837

26381501

Cylinder Head Cylinder & Piston Assembly Piston Pin Connecting Rod Venturi Nozzle For Remote Needle Propeller Nut Propeller Washer Drive Hub Thrust Washer Crankcase Crankshaft Cover Plate Assembly Cover Plate Ratchet Spring Needle "O" Ring Set Screw Head Gasket Screw Set Glow Plug A3 871 Silencer Pressure Fitting Assembly Screw Fixing Screw(N.+M2.6X25 2pcs.) E-2030 Silencer Pressure Fitting Assembly Screw Fixing Screw(N.+M3X27 2pcs.)

Description

Code No.

-1

-2

-3

-4

-5

-6

N.+M3X8

N.+M3X12

S.3X3

M3.5

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-40/46LA-S)

✽

ENGINE PARTS LIST

(MAX-40/46LA-S)

Specifications are subject to alteration for improvement without notice.

40LA-S

46LA-S

1 2 3 4 5 6 7 8 9 0

= q w e r

-1

-2

-3

-4

-5

-6

24004000

24004100

24003010

24003100

23356000

45806000 24005000 23312000

23210007 24009000 24008000 22020001

24001001

23364000

24001100

24014100 24007110 24007120 26582900 24081970 24981837 26381501 26711305 26582910 26582920 24013000 71605300 23325020 22681957 23325320 22625404

21381980

23302000

Cylinder Head Cylinder & Piston Assembly Piston Pin Connecting Rod Venturi Nozzle For Remote Needle Propeller Nut Propeller Washer Drive Hub Thrust Washer Crankcase Crankshaft Gasket Set Cover Plate Needle Valve Assembly B racket Needle Valve Assembly Needle "O" Ring Set Screw Ratchet Spring Needle Valve Body Needle Valve Body Retaining Screw Screw Set Glow Plug A3 E-3030 Silencer Pressure Fitting Assembly Screw Retaining Screw(2pcs.)

Description

Code No.

4.07 cc (0.249 cu.in.

)

18.0mm (0.709 in.

)

16.0mm (0.630 in.

)

2,000

16,000 r.p.m.

0.6 bhp / 15,000 r.p.m.

185.5g (6.54 oz.

)

■

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.

129.5g (4.56 oz.

)

■

MAX-15/25LA-S THREE VIEW DRAWING

Displacement Bore Stroke Practical R.P.M. Power output Weight

25LA-S SPECIFICATIONS

Displacement Bore Stroke Practical R.P.M. Power output Weight

15LA-S SPECIFICATIONS

( )15LA

Dimensions(mm)

6.49 cc (0.396cu.in.

)

21.2 mm (0.835in.

)

18.4 mm (0.724in.

)

2,000

16,000 r.p.m.

1.0 bhp / 15,000 r.p.m.

267.5g (9.43oz.

)

■

7.64 cc (0.467cu.in.

)

23.0 mm (0.906in.

)

18.4 mm (0.724in.

)

2,000

16,000 r.p.m.

1.2 bhp / 15,000 r.p.m.

263.5g (9.29oz.

)

■

MAX-40/46LA-S THREE VIEW DRAWING

Dimensions(mm)

Displacement Bore Stroke Practical R.P.M. Power output Weight

40LA-S SPECIFICATIONS

46LA-S SPECIFICATIONS

Displacement Bore Stroke Practical R.P.M. Power output Weight

O.S. GENUINE PARTS & ACCESSORIES

■

RADIAL MOTOR MOUNT

(71909310) for 15LA-S (71908100) for 25LA-S (71906200) for 40,46LA-S

/ "-28

(21125108) for 15LA-S (22325100) for 25LA-S (23325100) for 40,46LA-S

(23024008) for 25LA-S

■

SUPER SILENCER

■

SPINNER NUT

■

LONG PROPELLER NUT SET

■

BUBBLESS WEIGHT

■

SUPER FILTER (L

)

■

SILENCER EXTENSION

ADAPTORS

■

GLOW PLUG

■

LONG SOCKET WRENCH

WITH PLUG GRIP

(22325030) for 25LA-S

(73101000) for 25 46LA

(72403050)

(71521000)

(71605300)

E-2030S

(23325030) for 40,46LA-S

E-3030S

M5 (20824005) for 15LA-S

/ "-28(L)

(23024009) for 40,46LA-S

(71531000)

(Bubble Eliminating Tank Weight)

110100

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

O.S. engine MAX-15, MAX-40, MAX-46, MAX-25, 15LA-S Owner's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual