O.S. Engines 21TM User Manual
It is of vital importance, before attempting to operate
your eng ine, to read the gene ral '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.
1
2-5
6
7
8
12
22
25
23-24
26-29
8-10
13-16
30-33
17-19
20-22
10
11
CONTENTS
STARTING THE ENGINE & RUNNING-IN
FINAL ADJUSTMENT
CARBURETOR CLEANLINESS
CARE AND MAINTENANCE
CHECKING THE ENGINE
TROUBLE SHOOTING
ENGINE EXPLODED VIEW & PARTS LIST
CARBURETOR EXPLODED VIEW &
PARTS LIST
O.S. GENUINE PARTS & ACCESSORIES
THREE VIEW DRAWING
34-37
SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE
ENGINE CONSTRUCTION
NOTES WHEN APPLYING AN ELECTRIC
STARTER
ABOUT THE ENGINE
BEFORE STARTING
BASIC ENGINE PARTS
CARBURETOR CONTROLS
FACTS ABOUT GLOWPLUG
INSTALLATION
38
39-40
2
!
!
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.
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
Th e se co v er ev e nts wh ich
mig h t inv o lve se rious (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.
3
!
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 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.
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.
•
•
•
•
4
!
This engine is intended for model cars.
Do not attempt to use it for any other
purpose.
Mount the eng ine 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.
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
•
•
•
•
•
•
5
!
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.
•
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.
•
Before starting the engine, always check
the tightness of all the screws and nuts
especially those of joint and movable
parts such as throttle arm. Missing
retightening the loose screws and nuts
often causes the parts breakage that is
capable of harming you.
6
Piston
Cylinder Liner
Crankshaft
ENGINE CONSTRUCTION
With this engine, the piston will
feel tight at the top of its stroke
(TDC) when the engine is cold.
This is normal. The cylinder bore
has a slight taper. The piston
and cylinder are designed to
achieve a perfect running
clearance when they reach
operating temperature.
Near TDC
Slight taper
When the engine is cold.
When the engine is hot.
7
NOTES WHEN APPLYING
AN ELECTRIC STARTER
Do not over-prime. This could
cause a hydraulic lock and damage
the engine on application of the
electric starter.
If over-primed, remove glowplug,
close needle-valve and apply
starter to pump out surplus fuel.
Cover the head with a rag to
prevent any pumped out fuel from
getting into your eyes.
8
Standard accessories
Glow Plug LC3
Exhaust Seal Ring 1piece
ABOUT THE ENGINE
Exhaust Manifold for Revo
Items necessary for starting
Tools, accessories, etc.The following items are
necessary for operating the engine.
BEFORE STARTING
FUEL
Generally, it is suggested that the user selects a fuel
that is commercially available for model two-stroke
engines and contains 10-30% nitromethane. As a
starting point, we recommend a fuel containing 20%
nitromethane, changing to a fuel containing more
nitro if necessary. When the brand of fuel is
changed, or the nitro content increased, it is
advisable to repeat the running-in procedure
referred to in the RUNNING-IN paragraphs. Please
note that with high-nitro fuels,
although power may be increased
fo r co m peti t ion purp o ses,
glowplug elements do not last as
lon g and engine life will be
shortened.
T-Maxx and Revo are trademarks of Traxxas Corp.
Exhaust Manifold for T-Maxx
These engines are designed especially to power
the T-Maxx or Revo. Purposely designed LC3
glow plug is supplied with the engine for
improved power, fuel economy and durability.
The carburetor offers easy handling as well as
high performance.
9
!
!
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.
FUEL FILTER
GLOWPLUG IGNITER
Commercialy available handy
glowplug heater in which the
glowplug battery and battery
leads are integrated.
To be installed in the fuel line
between fuel tank and carburetor
to prevent foreign matter from
entering the carburetor.
FUEL PUMP
For filling the fuel tank, a simple,
polyethylene "squeeze" bottle,
with a suitable spout, is required.
SILICONE FUEL LINE
Heatproof silicone tubing of
approx. 5mm o.d. and 2mm i.d.
is required for the connection
between the fuel tank and
engine.
10
TOOLS
HEX SCREWDRIVER
SCREWDRIVER
Necessary for engine installation.
1.5mm, 2mm, 2.5mm, 3mm
Necessary for carburetor adjustments.
No.1, No.2, etc
LONG SOCKET WRENCH WITH PLUG GRIP
Recomm ended for easy rem ov al and
replacement of the angled and recessed
glo wplug, the O.S.Long Socket Wrench
incorporates a special grip.
Heatsink Head
Crankcase
Mounting Lugs
Exhaust
Carburetor
Type 11K
Crankshaft
Rear Adaptor
BASIC ENGINE PARTS
MAX-21TM (T-Maxx)
11
CARBURETOR CONTROLS
11K, 11K-R
The Needle-Valve:
The Mixture Control Valve:
Four adjustable controls are provided on
this carburetor.
For adjusting the mixture strength when the
throttle is fully open.
For changing the mixture strength at mid
speed and acceleration. (Do not rotate the
screw more chan one turn.)
The Throttle Stop Screw:
For setting the minimum idle speed:
For adjusting the mixture strength at partthrottle and idle speed, to obtain steady
idling and smooth acceleration to mid speed.
The Metering Needle:
NOTE: Readjustment may be necessary,
occasionally to allow for changes in fuel
formula gear ratio or clutch engagement
point.
Metering Needle
Throttle Stop
Screw
Mixture Control Valve
Needle Valve
Thermo Insulator
12
FACTS ABOUT GLOWPLUGS
The role of the glowplug
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items.
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 LC3. Carefully install plug finger-tight, before final
tightening with the correct size plug wrench.
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of
nitromethane.
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.:
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.
13
INSTALLATION
First, remove the original engine, from the
engine mount.
Install the flywheel and
clutch.
Install the engine on the engine mount with
ground wire.
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