O.S. engine MAX-25LA Setup guide

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.
●
●

CONTENTS
SAFETY INSTRUCTIONSAND WARNINGS
ABOUT YOUR O.S. ENGINE
INTRODUCTION
INSTALLATION OF THE ENGINE
INSTALLATION OF SILENCER
BEFORE STARTING
ADVICE ON SELECTION OF FUEL,
GLOW PLUG & PROPELLER
STARTING THE ENGINE
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
10LATHREE 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
15/25LATHREE VIEW DRAWING
36
1

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.
2

WARNINGS
Model engine fuel is poisonous. Do not
allow it to come into contact with the eyes
or mouth.Always store it in a
clearlymarkedcontainerand
out of the reach of children.
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
anythingelsewhichmightignite
it.Donotsmokeorallowanyone
else to smoke, near to it.
•
3

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.
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.
4

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 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
inanyway,unlessyouarehighlyexperienced
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.
•
•
5

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!
6

INTRODUCTION
THEMAX-10LA,15LA,25LAhave 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
techniciansare combined to ensurea 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

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
12mm min.
12mm min.
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 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 that the mounting beams are parallel
and that their top surfaces are in the same plane.
At least
12mm(1/2")
At least
12mm(1/2")
3mm steel nuts
8

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
Modelenginesgenerateconsiderableheat.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.
Reminder!
9