O.S. Engines 18CV-RX User Manual

It is of vital importance, before attempting to
operate your engine, to read the general

'SAFETY INSTRUCTIONS AND WARNINGS'

section on pages 2-5 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.

SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE

INTRODUCTION

BASIC ENGINE PARTS

INSTALLATION

SUPER AIR CLEANER 203

NOTES CONCERNING
THE RECOIL STARTER

GLOWPLUG

TOOLS, ACCESSORIES, etc.

CARBURETOR CONTROLS
PRESSURIZED FUEL SYSTEM

CONTENTS

STARTING THE ENGINE &



2-5

8-9

9-11

11-12

12-13

13-14

15
15

RUNNING-IN ('Breaking-in)

IF THE ENGINE FAILS TO START

6

FINAL ADJUSTMENT

7

CARBURETOR CLEANLINESS

CARE AND MAINTENANCE

ENGINES EXPLODED VIEW &
PARTS LIST

CARBURETOR EXPLODED VIEW &
PARTS LIST

O.S. GENUINE PARTS & ACCESSORIES

THREE VIEW DRAWING

MEMO

1

16-17

18

18-19

20

21

22-25

26-27

28-29

30-31

32

SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE

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.

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

These cover events which
might involve serious (in
extreme circumstances, even
fatal) 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.

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

These cover the many other
possibilities, generally less obvious
sources of danger, but which, under
certain circumstances, may also
cause damage or injury.

2

Never operate your engine in an en­closed 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

NOTES

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
more 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.

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 line from the tank.

Do not attempt to disassemble the
recoil starter of the 18CV-RX.
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.

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 it is rotated over
compression WITHOUT the glowplug
battery being reconnected.

5

INTRODUCTION

The MAX-18CV -R and MAX-18CV-RX are
high-perfomance engines for 1/10 class
R/C cars.
The 18CV -RX is a recoil starter version.
Newly developed 11G slide valve
carburetor is equipped.

Standard accessories

Glow Plug No.8
Super Air Cleaner 203 Assembly

Engine Mount Spacer (for 18CV-RX)

Instruction manual

NOTE:

As delivered, the engine has its
carburetor lightly fit into its intake.
Secure it changing its angle according
to the car chassis.

NOTE:
With this engine, the piston will feel tight
at the top of its stroke when the engine is
cold. This is normal. The piston and
cylinder are designed to achieve a
perfect running clearance when they
reach their normal running temperatures.

About Head Gasket

These engines are fitted with two head gaskets
of 0.1mm thick and 0.2mm thick. It is
suggested to adjust the total thickness
according to atmospheric temperature,
humidity and glowplug used.

At early stage of running-in, when a glowplug
tends to burn out early or when high
nitromethane content fuel is used, try to run
the engine as it is.

When low nitromethane content fuel is used,
try to run the engine removing a 0.1mm
gasket.

6

BASIC ENGINE PARTS

Carburetor

Beam Mount

Crankshaft

Drive Hub

Crankcase

Heatsink Heat

Starter Handle

Recoil Starter
Assembly No.5

MAX-18CV-RX

INSTALLING THE GLOWPLUG

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

Glow plug

Washer

7

INSTALLATION OF THE CARBURETOR

As delivered, the engine has its carburetor
lightly fit into the intake boss. Secure it as
follows.

Loosen the retainer screw, rotate the

1.
carburetor to its correct position and make
sure that it is pressed well down into the
intake boss, compressing the rubber gasket,
before retightening screw.

Rotate the retainer screw gently until it

2.
stops, then tighten a further 60-90˚.
Do not overtighten the screw as this will
damage the carburetor body.

Rotate the retainer nut
gently until it stops.

Tighten a further 60-90˚

8

ENGINE INSTALLATION

Make sure that the vehicle's engine mounting
surfaces are level and in the same plane. Poor
installation may cause distortion of the
crankcase, bearings, etc., resulting in erratic
running and loss of performance.
The recommended screws for securing the
engine are 3mm or 4-40 steel Allen hexagon
socket type.
If existing holes in the engine mount do not align
perfectly with engine mounting lugs, enlarge
them slightly with a needle-file so that screws
enter vertically.

Chassis

Chamfer inside edges of bearers.

Avoid forcing the screws. Secure with locknuts.
If the bottom of the recoil starter housing would
otherwise touch the car chassis, fit the engine
mount spacers (supplied) between the
engine's mounting lugs and the engine mount.
Use the M3x15 screws provided. With some
vehicles, it may be necessary to make minor
trimming modifications to chassis or body
when fitting the engine.

NOTE:
Where spacers are supplied joined in pairs
(see sketch) separate them as shown.
Either face may be placed downwards.

Mount Spacer

Separate

Engine Mount

Engine Mount Spacer

AIR CLEANER TYPE 203

This is a heavy-duty wet type air cleaner that has
been developed specifically for 3.5cc 'off-road'
model car engines. It is more compact than the
former O.S. SUPER AIR CLEANER 202 and this
makes it easier to install within a car body.

203 Intake Elbow

Element Base

Filter Element

End Plate

Retaining Screw

NOTE:
The element is already impregnated with a special
filter oil. As this oil is very sticky, take care, when
handling it, to prevent dust or dirt from adhering to
the element. If your fingers become contaminated,
wash them with soap and water.

9

"O" Ring

ASSEMBLY

Insert the filter element on the element base.

Fit the end plate with retaining screw, making sure
that the element fits correctly between the end
plate and base.

Insert the joint pipe on the element base and
secure it with "O" ring.

Fit the end plate, retaining screw, making sure that
the element fits correctly between the end plate and
base.

Element misaligned

REPLACMENT OF ELEMENT

NOTE:
During storage, the oil may have become unevenl y
dispersed through the element. This will be
indicated if the blue colour of the element material
appears patchy. In this case, place the element in a
small plastic bag and gently rub the element
between finger and thumb to redistribute oil.

It is advisable to replace the filter element after each
hour of running time. Be careful not to enter the dirt
and dust into the carburetor.

INSTALLATION

Carefully clean the carburettor, removing any old
adhesive or sealant that may have been previously
used on the outside of the air intake.

"O" Ring

10

FURTHER PRECAUTIONS

When removing the air cleaner, check the inside of the
element base and carburetor venturi. If any dirt is
detected, this indicates that the filter element was
incorrectly fitted or should have been replaced earlier.
In this event, it is vitally important to wash out the inside
of the engine thoroughly, with alcohol or fuel, before it
is used again, otherwise rapid wear of the
piston/cylinder assenbly, bearings, connecting-rod,
etc., will occur. Obviously, it will be necessary to carry
out the same procedure with the air cleaner and to
replace the filter element.

NOTE:
Be careful not to splash alcohol or fuel over the

filter element, or the filter oil will be washed away,
and the filter capacity will be lowered.

NOTES CONCERNING THE RECOIL STARTER

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.

The starter prevents the engine from being ro­tated in the wrong direction.The unit will be
damaged if you attempt to force the flywheel in
the opposite direction (i.e. clockwise when
viewed from the crankshaft end).

11

( 18CV-RX ONLY)