O.S. engine MAX-15LD Setup guide

It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-5 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 vehicle, radio control equipment, etc.,
are accessible for checking at the same time.
●
●

CONTENTS
SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE
INTRODUCTION, BASIC ENGINE PARTS
ENGINE SHIELD, INSTALLATION
THROTTLE LINKAGE
AIR CLEANER
NOTES CONCERNING
THE RECOIL STARTER
GLOWPLUGS
TOOLS, ACCESSORIES, etc.
CARBURETOR CONTROLS
STARTING THE ENGINE &
RUNNING-IN('Breaking-in)
IF THE ENGINE FAILS TO START
FINALADJUSTMENT
CARBURETOR CLEANLINESS
CARE AND MAINTENANCE
PARTS REPLACEMENT
EXPLODED VIEW &
ENGINE PARTS LIST
CARBURETOR EXPLODED VIEW
& PARTS LIST
O.S. GENUINE PARTS &
ACCESSORIES
THREE VIEW DRAWING
MEMO
2 ~ 515
16
~ 17
17
~ 18
18
~ 19
20
~ 23
26
~ 27
24
25
28
7
~ 8
8
~ 9
9
~ 10
10
~ 11
11
~ 12
13
~ 15
12
6
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 applies basically to ALL MODEL ENGINES and 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 poi-
sonous. 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
whichmightigniteit.Donot
smokeorallowanyoneelse
to smoke, near to it.
Never operate your engine in an en-
closed space. Model engines, like
automobile 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.
••
•
•
3

This engine is intended for model cars.
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.
Fit an effective silencer (muffler).
Frequent close exposure to a noisy
exhaust (especially in the case of the
most powerful highspeed engines)
may eventually impair your hearing
and such noise is also likely to cause
annoyance to others over a wide area.
The wearing of safety glasses is also
strongly recommended.
Take care that the glowplug clip or
battery leads do not come into contact
with rotating parts. Also check that the
linkage to the throttle arm is secure.
For their safety, keep all onlookers
(especially small children) well back
(at least 20 feet or 6 meters) when
preparing your model for running.
NOTES
•
•
•
•
•
•
4

NOTES
To stop the engine, fully retard the
throttle stick and trim lever on the
trans-mitter, or, in an emergency, cut
off the fuel supply by pinching the fuel
delivery tube from the tank.
•
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 it is rotated over
compression WITHOUT the glowplug
battery being reconnected.
•
Do not attempt to disassemble the
recoil starter of the 12LD-X and 15LD-
X. If you do so, the very strong spring
inside will be suddenly ejected. This
can be very dangerous.
Do not extend the starter cord more
than 45cm (18"). Do not abruptly
release the operating handle. Allow
the cord to rewind smoothly while
still holding the handle.
•
•
Pull the operating handle straight out
when starting the engine, so that the
cord does not rub against the vehicle
body or engine. This will help prevent
the cord from being damaged by
abrasion or engine heat.
•
5

INSTALLING THE GLOWPLUG
Fit washer to glowplug and
insert carefully into cylinder-
head, making sure that it is
not cross-threaded
before tightening firmly. Glow plug
Washer
ENGINE SHIELD
If the engine shield has to be removed, e.g. for
access to the carburettor, etc., apply a little
LOCTITE liquid
polymer sealant to the
two crankcase lug
screw holes when
reinserting the fixing
screws.UseLOCTITE
sparingly, as excess
sealant will have a
deleterious effect on
the shield material.
Apply a little LOCTITE
to these screw holes.
INSTALLATION OF ENGINE
Make sure that the chassis is flat and free from
flaws or dirt. The recommended screws for
securing the engine to the chassis are 3mm (8
to 10mm long ).
In the case of the 12/15LD-X, fit the engine
mount spacers between the engine and
chassis to avoid interference between starter
housing and chassis.
Divide the spacers into lengths.
Mount Spacer
Separate
Mount Spacer
Chassis
3mm Screw
7

INSTALLATION OF E-1000 SILENCER (12/15LD
(
T
)
.LD-X
(
T
)
)
Fit the nipple (supplied) to
the silencer, applying heat-
resistant epoxy sealant at
the roor of the fitting (See
sketch).
Before installing the engine
in the chassis, secure the silencer to the en-
gine with M3X27mm screws.
Seal here applying
heat-resistent
epoxy sealant.
MODIFICATION OF O.S. E-1000 SILENCER FOR
PRESSURIZED FUEL SUPPLY
•
•
THROTTLE LINKAGE
The throttle-arm ball-link is adjustable. Loosen
3mm set-screw and adjust the link so that link-
age rod and upper plate become parallel, and
then retighten it securely.
If the linkage rod and upper plate are not paral-
lel, throttle valve will not move smooth-ly and
may dam-age the carburettor.
Adjust the ball link position so that
linkage rod and upper plate become
parallel by loosening 3mm set-screw.
Upper plate
Throttle servo
3mm set-screw Chassis
AIR CLEANER
The air cleaner of this engine is integrated with
the engine shield. It contains a specially im-
pregnated filter element which prevents highly
damaging dust and dirt from being drawn into
the engine through the carburettor.
An O-ring is fitted between the engine shield
and carburettor to exclude air leaks.
8

•
•
•
•
◆
◆
◆
NOTES CONCERNING THE RECOIL STARTER
( 12/15LD-X ONLY)
REMINDER!
◆
◆
Do not attempt to disassemble the recoil
starter. If you do so, the very strong
spring inside will be suddenly ejected.
This can be very dangerous.
Do not extend the starter cord more than
45cm(18"). Do not abruptly release the
operating handle. Allow the cord to rewind
smoothly while still holding the handle.
Pull the operating handle straight out
when starting the engine, so that the cord
does not rub against the vehicle body or
engine.
This will help prevent the cord from being
damaged by abrasion or engine heat.
Try to avoid spilling fuel over the starter
unit and its cord. Some fuels have a
detrimental effect on these parts.
FILTER ELEMENT AND ITS REPLACEMENT
The elements are already impregnated with a
special filter oil. As this oil is very sticky, take care,
when handling them, to prevent dust or dirt from
adhering to the elements. If your fingers become
contaminated, wash them with soap and water.
During storage, the filter oil may become unevenly
dispersed through the element. This will be
indicated if the blue colour of the element material
appears patchy. In this case, place element in a
small plastic bag and gently rub it between finger
and thumb to redistribute the oil.
When fitting the element, be careful not to leave
spaces through which foreign matter may be
drawn.
It is advisable to replace the
element with a new one
after not more than one
hour of running time.
Always remove con-
taminated element carefully,
to ensure that dirt cannot
enter the carburettor.
Be careful not to
leave gaps.
9

Glowplug life
Particularly in the case of very high performance engines,
glowplugs must be regarded as expendable items.
Fit 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.:
•
•
•
GLOWPLUGS
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.
Since the compatibility of glowplug and fuel may have
a marked effect on performance and reliability, it may
be worthwhile to choose the R/C type plug found
most suitable after tests. Recommended O.S. plugs
are No.8, A3, and A5. Carefully fit plug finger-tight,
before final tightening with the correct size plug
wrench.
The starter prevents the engine from being
rotated in the wrong direction.The unit will
be damaged if you attempt to force the fly-
wheel in the opposite direction (i.e. clock-
wisewhen viewed fromthecrankshaft end).
NOTE:
Because, in the interests of personal safety,
dismantling of the starter mechanism is
strongly discouraged, the Recoil Starter is
available for replacement only as a pre-
assembled unit.
However, some related parts, such as
Starting Shaft and Rear Adaptor, are
obtainable separately. (See Parts List.)
◆
10

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.
•
•
•
•
•
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the
engine.
FUEL
Use only top quality methanol-based model engine
fuel.For consistent performance and long engine life,
it is advisable to use fuel containing AT LEAST 18%
lubricant.Thisengineisdesignedtorunonbothlowand
high nitromethane content fuels,i.e. from mild mixtures
containing a few percent of nitromethane, up to high-
speed racing fuels containing 40% nitromethane.
Generally, power output is increased
- up to a certain
point - asthenitromethanecontentofthefuelisincreased.
Asastartingpoint,werecommendafuelcontaining10-
20% nitromethane, changing to a fuel containing more
nitroonlyifnecessary.Whenthenitrocontentofthefuel
isincreasedorthebrandoffuelischanged,itisadvisable
to initially run the engine with a richer needle-valve
setting,sothattheoptimumsettingforthenewfuelmay
be rechecked as described in the RUNNING-IN
paragraphs. When engines are run at very high speeds
and on high-nitro fuels, glowplug elements do not last
so long.
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.
Keepitawayfromopenflame,excessiveheat,
sources of sparks, or anything else which
might ignite it.
Reminder!
GLOWPLUG BATTERY
The power source for heating the glowplug may be
either
a large heavy-duty 1.5Volt dry cell, or a 2-Volt
rechargeable
lead-acid cell with extended leads (or a
resistance) to reduce the applied voltage to
11

BATTERY LEADS
These are used to conduct current from the battery to
the glowplug. For convenience,special leads with a
suitable clip to fit the glowplug terminal, are
commercially available.
LONG SOCKET WRENCH
Recommendedforeasyremovalandreplacementofthe
angled and recessed glowplug, the O.S.Long Socket
Wrench incorporates a special grip. (See Parts List)
SILICONE TUBING
Heatproof silicone tube of approx. 5mm o.d. and
2mm i.d. is required for the connection between the
fuel tank and engine.
FUEL BOTTLE OR PUMP
For filling the fuel tank, a simple, polyethylene
"squeeze" bottle, with a suitable spout, is required. Al-
ternatively, one of the purpose-made manual or elec-
tric fuel pumps may be used to transfer fuel directly
from your fuel container to the fuel tank.
ELECTRIC STARTER AND STARTER BATTERY
Use an electric starter with 12-volt battery for starting
the MAX-12LD and MAX-15LD.
CARBURETOR CONTROLS (10F)
The Needle-Valve:
•
The Mixture Control Screw:
•
The Throttle Stop Screw:
For setting the minimum idling speed.
•
Needle Valve
Throttle Stop Screw
NOTE:
Readjustment may
be necessary, occa-
sionally to allow for
changes in fuel for-
mulae, gear ratio or
clutch engagement
point.
Three adjustable controls are provided on this
carburetor.
For adjusting the mixture strength when the throttle
is fully open.
For adjusting the mixture strength at part-throttle
and idling speeds, to obtain steady idling and
smooth acceleration to mid speeds.
Mixture Control Screw
12

The somewhat violent changes of vehicle attitude
that occur in off-road running, combined with the
fact that, in buggy type cars, the fuel tank is often
located some distance from the carburetor, means
that fuel 'head' at the carburetor can vary and upset
running.Therefore,it is recommended that a muffler
pressurized fuel feed system be used.
Never run your vehicle without fitting the air cleaner.
Dust and dirt that may otherwise be drawn into the
engine will rapidly shorten its life.
PRESSURIZED FUEL SYSTEM
•
•
Silencer
Fuel Tank
Silicone tube
Connect suitable length of
Silicone tubing between fuel
tank and silencer.
STARTING THE ENGINE & RUNNING-IN ('Breaking-in')
The following procedure is suitable for these engines
when the O.S. T-1020 tuned silencer and a fuel
containing up to 30% nitromethane are used.
Use the same fuel as is to be employed for all initial
running and containing NOT LESS THAN 18%
lubricant.
Temporarily remove the glowplug to check that it
glows bright red when energized.
•
•
Open the Needle-Valve 2 turns from the fully closed
position.
Re-check the needle-valve
and throttle settings. Turn
the needle-valve clockwise
slowly and gently until it
stops. This is the fully
closed position.Do not use
force to turn the needle-valve beyond this point.
•
•
Open Close
Needle Valve
Switch on the transmitter and
receiver and set the throttle
very slightly opened from the
idling position.
•Approx.
0.3-0.5mm
13

DO NOT energize glowplug,
but apply electric starter to
draw fuel to carburetor.
Now connect glowplug battery
lead to heat the plug filament
and start the engine.
•
Rotating
Direction
Front
Rear
•
■
Starter Handle
In case of the 12/15LD-X
Push the choke button on
the fuel tank several times
to deliver the fuel to the
carburetor. (Do not over-
prime or the recoil starter
cannot be pulled.)
Pull the starter handle briskly straight out several
times to start the engine.
•
•
Whentheenginestarts,firstallowittooperateinshort
runsattheveryrichstartingsettings,withtheglowplug
batterystillconnectedandwithitsdrivingwheelsclear
of the ground.The rich mixture will, under these
conditions,provideadequatelubricationandcooling,
indicated by profuse smoke from the exhaust.
•
It is vitally important to set the
throttle at the correct position
before attempting to start the
engine.If the engine is
allowed to run with the
throttle too far open under
"no load" conditions, it will
rapidly overheat and may be seriously damaged.
Remember!
Next, disconnect the glowplug battery and try
running the car on the track. If the engine stalls, open
the throttle fractionally, but try to keep the engine
running as rich as possible: if it stops because of
being excessively over-rich, close the Needle-Valve
30˚ and try again.
Runthecaronthetrackuntilonetankoffuelhasbeen
consumed, then close the Needle-Valve 30˚ and run
the car for another full tank of fuel.
•
•
Repeat this procedure until 5 more tanks of fuel have
been consumed, during which time the throttle may
be opened for brief bursts of increased power. If the
engine stops at medium speeds, close the Mixture
Screw 45-90˚.
14

If the engine should need to be disassembled (e.g.
for cleaning or minor parts replacement) it is
advisable to return the Needle-Valve to the original
rich, starting setting and check whether further
running-in time is required before the car is raced
again. In the event of any major working parts (e,g,
piston/cylinder liner assembly) being replaced, the
complete running-in should be repeated.
Remember!
30º
Needle
The position of the needle-valve
when starting the engine.
Close the needle-valve approx.
30˚ after running the vehicle for
one full tank of fuel.
Repeat this procedure several
times.
30º
30º
To stop the engine, close the throttle to idling speed,
then shut it off completely with the trim lever on the
transmitter. To cut off the fuel supply, pinch the fuel
delivery tube to the carburetor.
•
Repeat this procedure until 5 more tanks of fuel have
been consumed, during which time the throttle may
be opened for brief bursts of increased power. If the
engine stops at medium speeds, close the Mixture
Screw 45-90˚.
IF THE ENGINE FAILS TO START
Check the following:
Glowplug battery discharged or glowplug defunct.
Fuel not reaching carburetor.
•
•
•
MAX-12/15LD-X
Engine flooded.
Do not over-prime. (This could
also cause hydraulic lock and
damage the engine on application
of the electric starter.)
Remove glowplug, close needle-
valve and apply starter to pump
out surplus fuel. At this time cover
the plug hole with a rag so that
splashing out fuel may not come
into your eyes or mouth.
15

Run the vehicle (with throttle fully open) over the
longest available straight course, in order to observe
the model's speed. Next return the car to the starting
point, close the Needle-Valve 30˚ and repeat the
run, taking note of the improvement in performance.
Continue with further runs, gradually reducing the
Needle-Valve setting and aiming to achieve the
highest straight-line speed. Remember, however,
that, if the Needle-Valve is shut down too far, the
engine will overheat and, accompanied by visibly
diminished exhaust smoke, the model will lose
speed. At this point, throttle down immediately, stop
the vehicle and reopen the Needle-Valve 30˚.
Having established the optimum Needle-Valve
setting, check the Mixture Control Valve setting as
follows.
With the engine running, close the throttle and allow
it to idle for about five seconds, then reopen the
throttle fully. If, at this point, the engine puffs out an
excessive amount of smoke and the vehicle does
not accelerate smoothly and rapidly, it is probable
that the idling mixture is too rich.
FINAL ADJUSTMENT
•
•
•
In this case, turn the Mixture Control Valve
clockwise 45~90˚. If, on the other hand, the engine
tends to speed up momentarily and then cut out
abruptly when the throttle is opened,the idling
mixture is too lean. Correct this by turning the
Mixture Control Valve counter-clockwise 45~90˚.
Warning!
NOTE:
Mixture Control Valve adjustment should be made
in steps of not more than 45~90˚, carefully
checking the effect,on throttle response, of each
small adjustment.
Carry out adjustments patiently, under actual
running conditions, until the engine responds
quickly and positively to the throttle control.
Mixture adjustments (whether via the Mixture
Control Valve, or the Needle-Valve) cannot be
made accurately under 'no-load' conditions,
which, in any case, are not advised, since such
operation carries the risk of seriously damaging
the engine through over-revving and overheating.
•
•
16

With the optimum mixture control position, light
smoke is visible during high speed running,and the
engine revolutions increase smoothly during
acceleration. Remember that, if the engine is
operated with the fuel/air mixture slightly too lean, it
will overheat and run unevenly. As with all engines,
it is advisable to set both needle-valve and mixture
control screw very slightly on the rich side of the best
rpm setting, as a safety measure.
If the engine runs too fast with the throttle closed,
the throttle stop screw should be turned counter-
clockwise to allow the throttle opening to be
reduced.
•
•
•
Finally, beyond the nominal break-in period, a slight
readjustment toward a leaner needle setting may be
required to maintain performance.
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on
its small fuel orifices remaining clear.
BALL LINK AND SLIDE VALVE EXTENSION
It is seldom necessary to separate the slide-valve
extension from the slide-valve itself. For cleaning,
withdraw this complete sub-assembly from the
carburetor body after removing the slide-valve guide
screw. Then wash with methanol or glow-fuel.
(Note: take care not to lose the guide screw;it is a
special one.)
When it is necessary to adjust the ball-link position,
loosen the ball-link retaining screw with a 1.5mm
hexagon key, re-align the ball-link and re-tughten the
screw firmly.
■
17

REALIGNMENT OF MIXTURE CONTROL VALVE
■
In the course of making carburetor adjustments, it is
just possible that the Mixture Control Valve may be
inadvertently screwed in or out too far and thereby
moved beyond its effective adjustment range.Its basic
position can be found by first rotating the Mixture
Control Valve until its slotted head is flush with the
carburetor body. The valve is then screwed in exactly
2.5 turn to re-establish its neutral position.
Mixture Control Valve
First rotate the Mixture Control Valve until
its slotted head is flush with the
carburetor body.
Then screw the valve in exactly 2.5 turn.
This is the standard position.
CARE AND MAINTENANCE
1.
2.
3.
The minute particles of foreign matter, that are
present in any fuel may, by accumulating and
partially obstructing fuel flow, cause engine
performance to become erratic and unreliable.
One of these filters, fitted to the outlet tube inside
your refueling container, will prevent the entry of
foreign material into the fuel tank. It is also
recommended that a good in-line filter be installed
between the tank and carburetor.
Do not forget to clean the filters regularly to remove
dirt and lint that accumulate on the filter screens.
Also, clean the carburetor itself occasionally.
At the end of each operating session, drain out any
fuel that may remain in the fuel tank.
Afterwards,energize the glow-plug and try to restart
the engine, to burn off any fuel that may remain
inside the engine. Repeat this procedure until the
engine fails to fire. Do this while the engine is still
warm.
18

4. Then, inject some after-run oil into the engine, and
rotate the engine with an electric starter for 4 to 5
seconds to distribute the oil to all the working
parts.
Note:
5.
Do not inject after-run oil into the carburetor as
this may cause the O-rings inside the carburetor
to deteriorate. These procedures will reduce the
risks of starting difficulties or corrosion after a
period of storage.
Finally, when cleaning the exterior of the engine,
use methanol or kerosene. Do not use gasoline or
any solvent that might damage the silicone fuel
tubing.
Caution:
The rear crankshaft bearing of this engine uses a
special plastic retainer. If the front housing needs
to be heated to remove or replace the bearing, do
not allow the bearing to exceed 120˚C (248˚F),
otherwise it may be damaged and rendered
unserviceable.
PARTS REPLACEMENT
Over a long period, depending on how well
your engine is protected from the ingress of
harmful dust and grit, and other causes of
wear and tear, loss of performance may
eventually occur in the form of reduced power,
unstable idling, overheating, etc. Inspection
may then reveal that the replacement of ball-
bearings, connecting rod, etc. is called for.
Contact the O.S. distributor in your country for
replace-ment parts, or full service.
19

MAX-12, 15LD/LD(T) EXPLODED VIEW
Type of screw C…Cap Screw M…Oval Fillister-Head Screw
F…Flat Head Screw N…Round Head Screw S…Set Screw
1
2
3
4
5
67
89
0-
=
q
w
e
N.+M3x27
C.M2.6x12(15LD)
t
r
N.+M2.6x15
M.+M2.6x12(12LD)
M.+M2.6x7
20
✽