O.S. Engines 21XZ-B VII - Manual

It is of vital importance, before attempting to operate your
engine, to read the general 'SAFETY INSTRUCTIONS
AND WARNINGS' in the following section 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.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
The advice which follows 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.
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 or abused. 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.
WARNINGS
NOTES
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.
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 operate your engine in an enclosed space.
Model engines, like automobile engines, exhaust
deadly carbon-monoxide. Run your engine only in
an open area.
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.
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.
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 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.
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.
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.
Piston
Cylinder
Liner
Crankshaft
Near TDC
Slight taper
When the engine is cold. When the engine is hot.
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.
As delivered, the engine has the carburetor
lightly fit into its intake. Secure it changing its
angle according to the car chassis.
NOTE
Please do not run on a public street, this could
cause serious accidents, personal injuries
and/or propetry damage.
Please do not run near pedestrians or small
children.
Please do not run in small or confined areas.
Please do not run where loud noises can disturb
others, such as hospitals and residential areas.
While Operating
ABOUT THE ENGINE
FUEL
Generally, it is suggested that the user selects a fuel that is
commercially available for model two-stroke engines 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 for competition purposes,
glowplug elements do not last as long and
engine life will be shortened.
Items necessary for starting
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the engine.
FUEL FILTER
To installed in the fuel line between fuel
tank and carburetor to prevent foreign
matter from entering the carburetor.
GLOWPLUG IGNITER
Commercialy available handy glowplug
heater in which the glowplug battery and
battery leads are integrated.
STARTER BOX
For starting the engine.
FUEL PUMP
For filling the fuel tank, a simple, polyethylene
"squeeze" bottle, with a suitable spout, is
required.
TOOLS
O.S. SPEED DRIVER TOOLS
O.S. SPEED PLUG WRENCH
O.S. SPEED
CLUTCH WRENCH & ADJUSTER
O.S. SPEED FLYWHEEL KEY
O.S. SPEED FLYWHEEL PULLER
Outer Head
Crankcase
Mounting Lugs
Exhaust
Cover Plate
Carburetor
Type 22B2
Crankshaft
BASIC ENGINE PARTS
Crankshaft Bearing (Front)
Metering Needle
Throttle Stop
Screw
Needle Valve Carburetor Reducer
Ball Link
Dust Cover
The Needle-Valve:
Three adjustable controls are provided on this
carburetor.
For adjusting air/fuel ratio (air-fuel mixture) at maximum
rpm (fully opened throttle).
The Throttle Stop Screw:
For setting the minimum idle speed:
For adjusting idle and acceleration feeling.
The Metering Needle:
NOTE:
The Metering Needle Valve is set at the standard
position when the engine leaves the factory,
readjustment may be necessary, occasionally to allow
for changes in fuel formula and climatic conditions
Readjust the controls only when satisfactory results
cannot be obtained with the standard positions
following the instructions mentioned in the
“CARBURETOR ADJUSTMENT” section.
INSTALLATION OF THE CARBURETOR
As delivered, the engine has its carburetor lightly installed
in the intake boss. Secure it as follows.
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.
Chamfer inside edges of bearers.
Do not allow bottom
of crankcase to
touch chassis.
Running- in is a procedure for an engine to come
close to actual running conditions (fuel, r.p.m.,
engine temperature, etc.).
Excessively rich running and prolonged low speed
running should be avoided. Prolonged low speed
running and low temperature running may result
in the oil in the fuel becoming gelled and the
piston/liner becoming stuck together.
PRESSURIZED FUEL SYSTEM
It is recommended that a muffler pressurized fuel
feed system be used so that the fuel may be stably
fed to the carburetor.
The following procedure is suitable when a fuel
containing 30% nitro-methane is used.
STARTING THE ENGINE & RUNNING-IN ('Breaking-in)
Turn the needle-valve clockwise until it stops.
This is the fully closed position.
Do not force it to turn further.
Needle Valve
Open
(Counter-clockwise)
Close
(Clockwise)
3 and 1/4 turns opened from the fully closed position.
Note:
Sketch shows the carburetor reducer removed.
Slide Valve
Carburetor Body
Metering Needle
Flush with the ball link body.
Ball Link
Set the throttle opening a
little wider (approx. 1mm)
than the standard setting
by adjusting the Throttle
Stop Screw.
approx 1mm
Attention:
It is vitally important to set the
throttle at the correct position
before starting the engine. If
the engine is allowed to run
with the throttle too far open
under ''no load'' conditions
(i.e. with the driving wheels not in contact with the
ground) it will rapidly over-heat and may be
seriously damaged.
NOTES ON OPERATION
Glow Plug P3 T-type head (Turbo head)
1piece
Exhaust Seal Ring 1piece
O.S. SPEED Dust Cap Set For 12-30 Class
3mm, 16mm, 18mm 1piece each
(Hot Type)
Standard accessories
Thermo Insulator
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.
1.
2.
Rotate the retainer nut
gently until it stops.
Tighten a further
120-180
Rotate the retainer screw gently until it stops, then
tighten a further 120-180 .
Do not overtighten the screw as this will damage the
thermo insulator.
Note
Be careful not to damage the O rings when
removing the carburetor retainer from the engine.
First, remove the retainer Retaining screw, then
pull out each part. Do not push the part in or
damage the O rings.
Retaining Screw
"O" Ring "O" Ring
Approx 0.5mm
2.
1.
4.
3.
[Standard Position]
[Fully closed position]
Slide Valve
Carburetor Body
CARBURETOR CONTROLS STANDARD POSITIONS
(POSITIONS WHEN THE ENGINE LEAVES THE FACTORY)
[Standard Position]
[Standard Position]
Note:
Be sure to use a collet supplied when use a
optional 28XZ Hyper Flywheel Set.
The engine bottom may interfere with chassis of
some models. In this case, file off the chassis
so that the engine may not interfere with the
chassis when it is installed.
NOTE
Set the carburetor controls at the standard positions
(positions when the engine leaves the factory.)
Switch the transmitter and make sure that each
linkage moves correctly.
Make sure rotating direction of the starter box is
correct (counter-clockwise seen from the front edge
of the crankshaft), and turn the engine with the
starter box to draw fuel into the engine.
Connect glowplug battery lead to heat the plug and
start the engine with the starter box.
When the engine does not start or stops right after
being started, try the followings.
Close the needle-valve approx. 90° from the
standard position.
5. When the engine starts, warm it up by repeatedly
increasing the rpm to medium speed and back
again to a fast idle with the mixture set very rich,
glowplug connected, and the driving wheels clear of
the ground. The rich mixture will provide adequate
lubrication and cooling, indicated by profuse
exhaust smoke.
6. When the engine is warmed up, disconnect the
glowplug battery and try running the car on the
track. If the engine stops soon after running at
around mid speed, the mixture is too rich. Close the
needle-valve 15~30°.
If the engine still stalls, close the metering needle
15~30°. Run the car on the track until one tank of
fuel has been consumed, then close the needle-valve
very little (within 10°).
Expressly for 1/8 off-road buggy racing competitions
GUARANTEE
This engine is constructed from the very best
materials available and to the very highest
engineering standards, using the most
advanced precision machinery. However, the
extremely high stresses imposed by car racing
operation under very severe conditions, as
well as stresses which are exacerbated by the
use of powerful fuels containing very high
concentrations of nitromethane, constitute
hazards which are beyond a manufacturer's
control. Accordingly, we regret that it is not
possible to extend our usual warranty terms to
this particular engine -i.e. no guarantee is
offered against material wear, or damage
resulting therefrom, in actual use.
Warning!
Do not touch rotating parts, engine and silencer
when stopping the engine as they become very hot,
and contact with them may result in a serious burn.
To stop the engine, close the
throttle to idle speed and shut it off
completely with the trim lever on the
transmitter then cut off the fuel
supply by pinching the fuel delivery
tube to the carburetor.
Fuel
How to stop the engine
Note:
In the event of any major working parts (e.g.
piston/cylinder liner assembly) being replaced or
the fuel being changed, especially to high nitro
fuel, the complete running-in should be repeated.
7. Repeat this procedure (close needle-valve very little
after one tank of fuel has been consumed) until approx.
2 liters of fuel have been consumed, extending
gradually the full throttle running time at the straight.
Carefully observe the exhaust smoke.
Be sure to run the engine with visible white smoke at all
times. If the smoke is not visible, the needle-valve is
closed too far.
Now the RUNNING-IN (Breaking-in) is completed.
MAX-
21XZ-B Ver.
The MAX-21XZ-B Ver.II is expressly designed for 1/8
off-road racing buggy featuring smooth acceleration
and easy handling.
Newly designed single-adjust carburetor ensures
easier adjusting.
The connection between the fuel tank and the engine.
2.5mm ID
O.S. SPEED SILICONE FUEL LINE (optional extra)