O.S. engine MAX-75AX-BE User 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.

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

20-21

28-31

15-17

SAFETY INSTRUCTIONS AND WARNINGS

ABOUT YOUR O.S. ENGINE

ENGINE CONSTRUCTION,

NOTES WHEN APPLYING AN ELECTTRIC STARTER

ABOUT THE ENGINE

BASIC ENGINE PARTS

BEFORE STARTING

INSTALLATION

INSTALLATION OF THE STANDARD ACCESSORIES

FUEL TANK LOCATION

MIXTURE CONTROLS

GLOWPLUG

CONTENTS

STARTING

RUNNING -IN, IDLING ADJUSTMENT CHART

MIXTURE CONTROL VALVE ADJUSTMENT

REALIGNMENT OF MIXTURE CONTROL VALVE,

SUBSEQUENT STARTINGPROCEDURE

TROUBLE SHOOTING WHEN THE

ENGINE FAILS TO START

CARE AND MAINTENANCE

ENGINE EXPLODED VIEW & PARTS LIST

CARBURETOR EXPLODED VIEW & PARTS LIST

O.S. GENUINE PARTS & ACCESSORIES

THREE VIEW DRAWING

34-35

36-37

38-39

40-41

11-14

18-19

42-43

24-27

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.

WARNINGS

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

anything else which might

ignite it. Do not smoke or allow

anyone else to smoke, near to it.

O.S. Bio - Ethanol fuel is not poisonous but

harmful. Do not allow it to be swallowed.

Always store it in a clearly marked

container and out of the reach of children.

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.

NOTES

Always check the tightness of the propeller

nut and retighten it, if necessary, before

restarting the engine. Also, check the

tightness of all the screws and nuts before

restarting the engine.

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

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 carburetor.

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!

Piston

Cylinder Liner

Crankshaft

ENGINE CONSTRUCTION

Near TDC

Slight taper

When the engine is cold. When the engine is hot.

With this engine, the piston

will feel tight at the top of its

stroke (TDC) when the engine

is cold. This is normal.

The cylinder bore has a

slight taper. The piston and

cylinder are designed to

achieve a perfect running

clearance when they reach

operating temperature.

NOTES WHEN APPLYING

AN ELECTRIC STARTER

Do not over-prime. This could

cause a hydraulic lock and damage

the engine on application of the

electric starter.

If over-primed, remove glowplug,

close needle-valve and apply

starter to pump out surplus fuel.

Cover the head with a rag to

prevent pumped out fuel from

getting into your eyes.

STANDARD ACCESSORIES

Glow Plug BE-3

(suppplied with the engine)

Needle Valve Extension Cable Set

E-4040 Silencer Assembly

Silencer Retaining Screw (M4x40 2pcs.)

ABOUT THE ENGINE

The MAX-75AX-BE has been developed and

designed to use O.S. Bio-Ethanol fuel only.

Therefore, some parts are different from

those of the MAX-75AX that use conventional

methanol based glow fuel. Also, special

attention is required in it’s handling.

This engine has been developed based on the

MAX-75AX, to use only O.S. Bio-Ethanol fuel.

It develops enough powerto fly general 61 size

sport models.

It is suggested to use propellers which develop

maximum r.p.m. of 8,500~9,500 so that you

may enjoy pleasant exhaust sound keeping it

low.

Glow plug, cylinder head, carburetor, drive hub

and silencer are different from those of the

MAX-75AX.

BASIC ENGINE PARTS

Cylinder head

Carburetor Type 61A-BE

Crankshaft

Propeller nut

Propeller washer

Drive Hub

Crankcase

Cover Plate

Glowplug

Beam Mount

Lock nut

Tools, accessories, etc. The following items

are necessary for operating the engine.

BEFORE STARTING

The choice of propeller depends on the design

and weight of the aircraft and 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

than those shown in the table may be used,

but remember that the propeller noise will

increase, due to higher rpm or if a larger-

diameter/lower-pitched prop is used.

Propellers

13x9-10, 14x6-8, 15x6

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.

Reminder!

Warning:

Make sure that the propeller is well

balanced. An unbalanced propeller and/or

spinner can cause serious vibration which

may weaken parts of the airframe or affect

the safety of the radio-controlled system.

DO NOT forget the WARNINGS and NOTES

on propeller and spinner safety given on

front pages.

Since the 75AX-BE is intended to

be started with an electric starter,

the addition of a spinner

assembly for centering the starter sleeve is

desirable. Use a heavy-duty, well balanced

spinner either of metal or plastic.

Spinner

It is suggested to use propellers which develop

maximum r.p.m. of 8,500~9,500 so that you

may enjoy pleasant exhaust sound keeping it

low.

FUEL

O.S. Bio-Ethanol fuel is not poisonous but

harmful. Do not allow it to be swallowed.

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!

A fuel tank of approximately

160~180cc capacity is suggested.

This allows around 10-12 minutes flying time,

dependent upon, the size of propeller and on

the amount of full-throttle to part-throttle

operation throughout the flight.

Fuel Tank

GLOW PLUG

Use the O.S. Bio-Ethanol fuel (BE-1).

Other fuel cannot be used with this engine.

Do not use conventional methanol based glow

fuel, or the engine will not run properly and

strong knocking may occur, which may cause

the propeller to fly off.

The engine is supplied with a special

glow plug (BE-3) designed for this

engine. Use 1.2V~1.5V the same as

conventional glow plugs.

This glow plug has a different thread

size for both the dia. and pitch

purposely so that conventional glow

plugs may not be installed.

1,2V〜1.5V

GLOWPLUG IGNITER

Commercialy available handy

glowplug heater in which the

glowplug battery and battery leads are integrated.

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 PUMP

Manual Electric

Electric Starter and

Starter Battery

Required when starting

the engine. 12-Volt lead-acid battery

Electric

Starter

Install a filter on the outlet tube of your

refueling container to prevent entry of

foreign matter into fuel tank. O.S. ‘Super Filters’

(large and small) are available as optional extras.

O.S. Super Filter (Fuel Can Filter)

To prevent the pickup from adhering to

the tank wall under suction and

restricting fuel flow, slots may be filed I

the end of the weight. Alternatively, an

O.S. Non-Bubble Weight is available as

an optional extra.

It is recommended to install a good

in-line filter between the fuel tank

and carburetor to prevent entry of

foreign matter into the carburetor.

O.S. Non-Bubble Weight

Fuel Filter SILICONE FUEL LINE

Heatproof silicone tubing of

approx. 5mm o.d. and 2.5mm i.d.

is required for the connection

between the fuel tank and engine.

8mm

TOOLS

HEX Screwdriver

SCREWDRIVER

Necessary for engine installation.

1.5mm, 2.5mm

Necessary for carburetor adjustments.

Phillips Screwdriver

No.2, etc.

Socket Screwdriver

5mm, 5.5mm, 7mm

LONG SOCKET WRENCH WITH PLUG GRIP

Recommended for easy removal and

replacement of the angled and recessed

glowplug, the O.S.Long Socket Wrench

incorporates a special grip.

End Wrenches

12mm, 14mm etc.

Needle Nose Pliers

It is suggested to use as heavy and rigid as possible engine mounting for highest performance and

safe running. Conventional wooden mounting beams should be of rigid hardwood and of at least

15mm or 5/8-in square section. Use at least 3mm steel screws, such as Allen type, with locknuts, for

bolting the engine to the bearers..

INSTALLATION

CORRECT

Top surfaces are in the same plane.

INCORRECT

Front view Side view

Re-align the surfaces

as necessary

Opposite beam

Top surfaces are not in the

same plane.

Engine does not rest firmly.

Top surfaces are not

in the same plane.

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

Radial motor mount (cast aluminum)

Tighten second nut

firmlydown onto first nut.

Tighten this nut first.

Steel washer

3mm steel nuts

3mm steel screw

Spring washer or

lock washer

15mm min.

15mm min. Hardwood such as

cherry or maple.

Spring washer

3.5mm

steel Allen screw

● Make sure that these mounting beams are

accurately aligned and firmly integrated with

the airframe, reinforcing the adjacent

structure to absorb vibration. Use 4mm or

larger steel screws, preferably Allen type

hexagon socket head cap screws, with

washers and locknuts, for bolting the engine

to the bearers.

O.S. Radial Motor Mount

A special O.S. radial motor mount (Code

No.71905200) is available, as an optional

extra, for use where firewall type mounting is

required.

THROTTLE LINKAGE

Before connecting the throttle to its servo,

make sure that the throttle arm and linkage

safely clear any adjacent part of the airframe

structure, etc., as the throttle is opened and

closed. Connect the linkage so that the throttle

is fully closed when the transmitter throttle

stick and its trim lever are at their lowest

settings and fully open when the throttle stick

is in its fully-open position. Carefully align the

appropriate holes in the throttle arm and servo

horn so that they move symmetrically and

smoothly through their full travel.

INSTALLING THE GLOWPLUG

Install washer on glowplug

and insert carefully into

cylinder-head, making sure

that it is not cross-threaded

before tightening firmly.

Glow plug

Washer

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. For this purpose a Needle

Valve Extension Cable Set is supplied with the

engine. If a longer extension is reguired, 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.

Needle Valve

Extension Cable Set

1.5mm Allen key.

Set Screw

INSTALLATION OF THE STANDARD ACCESSORIES

INSTALLING SILENCER E40400 Silencer

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. Keep your hands and face away from

exhaust gas or you will suffer a burn.

Reminder!

The exhaust outlet of the silencer can be

rotated by 90 degrees the following manner:

Loosen the locknut and assembly screw.

Set the exhaust outlet at the required posi-

tion by rotating the rear part of the silencer.

Re-tighten the assembly screw, followed by

the locknut.

Assembly screw

Locknut

Exhaust pressure nipple

Secure the silencer to the engine by means of

two retaining screws supplied after the engine

is securely mounted to a test bench or a

model.

It is recommended to seal the fitting faces of

engine exhaust and silencer with silicone

sealant.

Gasket

Baffle plate

Can be rotated

by 90 degrees.

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