O.S. Engines 21VZ-R 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.

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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.

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Keep these instructions in a safe place so that
you may readily refer to them whenever
necessary.

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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

GLOWPLUG

TOOLS, ACCESSORIES, etc.

CARBURETOR CONTROLS
STARTING THE ENGINE &

RUNNING-IN('Breaking-in)

IF THE ENGINE FAILS TO START

FINAL ADJUSTMENT

CONTENTS

2-5

9-10

10

11-12

13

13-14

CARBURETOR CLEANLINESS

BEFORE STARTING THE ENGINE

6

CARE AND MAINTENANCE

7

GUARANTEE

8

EXPLODED VIEW

ENGINE PARTS LIST
CARBURETOR EXPLODED VIEW &

PARTS LIST

O.S. GENUINE PARTS & ACCESSORIES

THREE VIEW DRAWING

1

15

16-17

17

18

19

20

21

22

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

!

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

!

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•

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 an 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.

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

•

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.

!

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NOTES

3

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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.

Install 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.

NOTES

•

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

!



•

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.

•

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.

NOTES

5

The MAX-21VZ-R Ver. a high performance

3.5cc class power unit for one-eighth-scale ra­dio-controlled 'Track racing' cars. It has been
designed to meet the exacting requirements of
the world's most expert drivers. An exhaustive
program of research, development and proto­type testing has resulted in one of the most
powerful production model racing car engines
currently available.

Standard accessories

Glow Plug P7
Exhaust Seal Ring

Cylinder-head gasket (0.1mm)

Dust Cap 3, 16, 18

BASIC ENGINE PARTS

Heatsink Head

Carburetor
Type 20K

Crankshaft

Exhaust

Cover Plate

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.

NOTE

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

INSTALLING THE GLOW PLUG

1.

Insert carefully into heatsink head, making
sure that it is not cross-threaded before
tightening firmly.

2. Install the exhaust seal ring supplied.

INSTALLATION OF THE CARBURETOR

As delivered, the engine has its carburetor lightly
install into its 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

2.
screw gently until it
stops, then tighten
a further 120-180˚.
Do not overtighten
the screw as this
will damage the
carburetor body.

Rotate the
retainer nut
gently until
it stops.

Tighten a
further
120-180˚

Mounting Lugs

Crankcase

The engine is fit with one each of 0.1mm and

0.2mm cylinder-head gasket when it leaves the
factory. Another 0.1mm head gasket is supplied
with the engine. You may add it at initial running­in, when a glow plug tends to burn out due to high
temperature and / or high humidity or when you
prefer fuel economy to power.

6

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 are
in alignment with the mounting holes.

Do not allow bottom
of crankcase to
touch chassis.

Chassis

Chamfer inside edges of bearers.

7