O.S. engine max-21RG-M 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
INSTALLATION
NOTES CONCERING
THE RECOIL STARTER
GLOWPLUG
TOOLS, ACCESSORIES, etc.
CARBURETTOR CONTROLS
STARTING & INITIAL
RUNNING-IN('Breaking-in)
ADJUSTMENT
2
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5
6
7
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8
8
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9
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10
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11
13
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15
16
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17
18
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19
20
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21
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CARE AND MAINTENANCE
CHECKING OF THE ENGINE
TROUBLE SHOOTING WHEN THE
ENGINE FAILS TO START
ENGINE EXPLODED VIEW
ENGINE PARTS LIST
CARBURETTOR EXPLODED VIEW
& PARTS LIST
O.S. GENUINE PARTS &
ACCESSORIES
THREE VIEW DRAWING
MEMO
12
19
23
24
25
26
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27
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 poison-
ous.Donotallowittocomeinto
contactwiththeeyesormouth.
Always store it in a clearly
markedcontainerandoutofthe
reach of children.
Modelenginefuelisalsohighly
flammable. Keep it away from
open flame, excessive heat,
sources of sparks, or anything
else which might ignite it. Do
notsmokeorallowanyoneelse
to smoke, near to it.
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.
•
3

This engine was designed for model boats.
Donotattempttouseitforanyotherpurpose.
Mount the engine in your model securely,
following the manufacturers' recommenda-
tions, using appropriate screws and lock-
nuts.
Fit an effective silencer (muffler). Frequent
close exposure to a noisy exhaust
(especially in the case of the most powerful
high-speed engines) may eventually impair
your hearing and such noise is also likely to
causeannoyancetoothersoverawidearea.
Take care that the glowplug clip or battery
leads do not come into contact with the
propeller or any other rotating parts. Also
check that the linkage to the throttle arm is
secure.
If your engine does not have a built-in recoil
starter, use an electric starter. The wearing
of safety glasses is also strongly
recommended.
When handling the boat immediately prior to
launching, be especially cautious.
Keep the propeller and other rotating parts
away from you.
NOTES
•
•
•
•
•
•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

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.
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.
NOTES
•
•
•
•
If your engine is fitted with a recoil starter,
pull the operating handle straight out when
starting the engine, so that the cord does
not rub against the hull or engine.
This will help prevent the cord from being
damaged by abrasion or engine heat.
•
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.
Do not attempt to disassemble the recoil
starter (if fitted). If you do so, the very
strong spring inside will be suddenly
ejected. This can be very dangerous.
5

MAX-21RG-MX
The O.S. "RG Series" is a high-performance
water-cooled marine engine for small radio-
controlled boats, especially sport type hulls.
A companion model, the MAX-21RG-MX in-
corporating a recoil starter system is also
available.
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.
We do not recommend running your boat
on the sea, or in any other saltwater
environment. Under such conditions, it is
difficult to prevent the engine from
becoming corroded and, eventually,
inoperative.
NOTE
•
•
Standard accessories
Glow Plug No.8
Flywheel No2E Exhaust Header Pipe
BASIC ENGINE PARTS
Carburettor
Type 20J
Water Cooled Head
Starter Handle
Recoil Starter
Assembly No.5
Beam Mount
Crankcase
Cranshaft
Glow Plug No.8
INSTALLING THE GLOWPLUG
Install the washer on the
glowplug and insert carefully
into cylinder-head, making sure
that it is not cross-threaded
before tightening firmly.
Glow plug
Washer
6

Insert the taper collet on the crankshaft, taking care
not to push the crankshaft to the cover plate end.
Select the screw
holes according to
the model.
INSTALLATION OF THE CARBURETOR
As delivered, the engine has its carburetor lightly
fitted into its intake boss. Secure it as follows.
Loosen the retainer screw, rotate the 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 stops, then
tighten a further 90-120˚.
Do not overtighten the screw as this will damage
the carburetor body.
1.
2.
Rotate the retainer nut
gently until it stops. Tighten a further 90-120˚
Crankshaft
Flywheel
Taper Collet
INSTALLATION OF THE FLYWEEL
INSTALLATION OF THE
EXHAUST HEADER PIPE
7

INSTALLATION
Make sure that the engine mounting beams in the
hull are parallel, with their top surfaces in the same
plane. If they are not, the engine will not rest firmly
as the engine mounting faces (undersides of the
mounting lugs) are precision machined to be flat
and in the same plane. Poor installation may not
only cause vibration, erratic running and loss of
performance, but may also damage the engine
itself by deforming the crankcase, cylinder, etc.
The mounting beams and adjacent hull structure
should be as rigid as possible so that the engine
may develop its full performance. Use 3mm steel
screws, such as Allen socket-head type, with
locknuts, for bolting the engine to the mounting
beams.
If the holes in the mounting beams do not align
exactly with the engine's mounting lugs, enlarge
them slightly with a needle file so that the mounting
screws pass through the holes smoothly without
being forced.
1.
2.
3.
Chamfer inside edges of bearers.
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.
8

◆
◆
NOTE: Because, in the interests of personal
safety, dismantling of the starter mechanism
isstrongly 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.)
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).
GLOWPLUG
Since the compatibility of the glowplug and fuel can
have a marked effect on performance and reliability, it
is suggested that the user selects the R/C type plug
found most suitable after practical experiments.
Generally, for a fuel containing about 30%
nitromethane, a medium heat range glowplug will be
suitable.
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.
For higher nitro fuel, a cold rated plug may be
required, whereas, for lower nitro fuel, a hot rated
plug may be best. However, the O.S. No.8 glowplug
may be employed irrespective of the nitro content of
the fuel.
9