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 model, radio control equipment, etc.,
are accessible for checking at the same time.
CONTENTS
SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE
NOTES ON INSTALLING,
COOLING-FAN AND CLUTCH
NOTES WHEN APPLYING AN ELECTRIC STARTER
INTRODUCTION, BEFORE STARTING
ENGINE PARTS NAME,
FACTS ABOUT GLOWPLUGS
INST ALLING THE GLOWPLUG,
INSTALLATION OF THE ENGINE
CARBURETOR CONTROLS
STARTING, RUNNING-IN ("Breaking-in")
2-5
6-7
7-8
9-12
13-14
15-16
17-18
18-20
ADJUSTMENT
SUBSEQUENT READJUSTMENTS
CARBURETOR CLEANLINESS
ADJUSTMENT CHART
INSTALLATION OF THROTTLE SERVO
CARE AND MAINTENANCE
TROUBLE SHOOTING
ENGINE EXPLODED VIEW & PARTS LIST
CARBURETOR EXPLODED VIEW & PARTS LIST
O.S. GENUINE PARTS & ACCESSORIES
THREE VIEW DRAWING
MEMO
1
21-23
24
25
26
27
28-31
32-33
34-35
36
37
38
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 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.
!
•
Never touch, or allow any
object to come into contact
with, the rotating parts.
Model engine fuel is poison-
•
ous. 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.
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 carbonmonoxide. 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.
!
NOTES
3
!
This engine was designed for model
•
helicopters. Do not attempt to use it for any
other purpose.
Mount the engine in your model securely, fol-
•
lowing 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 high-speed
engines) may eventually impair your hearing
and such noise is also likely to cause
annoyance to others over a wide area.
Check the linkage to the throttle arm before
•
each flight.
Avoid sudden high r.p.m. immediately after the
•
engine is started, as the clutch will engage and
you may be struck by the rotor.
NOTES
After starting the engine, carry out any needle-
•
valve readjustments after stopping the rotor by
closing the throttle to the lowest r.p.m..
Stop the engine before attempting to make
other adjustments to the carburetor.
Use an electric starter. The wearing of safety
•
glasses is also strongly recommended.
Press the rotor head down securely.
Take care that the glow plug clip or battery
•
leads do not come into contact with rotating
parts.
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.
4
!
Take care that loose clothing (ties, shirt sleeves,
•
scarves etc.) do not come into contact with the
rotor. Do not carry loose objects (such as pencils, screwdrivers, etc.) in a shirt pocket from
where they could fall through the rotor disc.
For their safety, keep all onlookers (especially
•
small children) well back (at least 20 feet or 6
metres) when preparing your model for flight. If
you have to carry the model to the take-off point
with the engine running, be especially cautious.
Hold the rotor securely and keep well clear of
spectators.
Warning! lmmediately after a glowplug-ignition
•
engine has been run and is still warm,
conditions sometimes exist whereby it is just
possible for the engine to restart when turned
over WITHOUT the glowplug battery being
reconnected. Remember this if you wish to
avoid the risk of an accident.
NOTES
5
Notes on installing cooling fan and clutch
Do not use a tool which
locks piston when installing
a cooling-fan and clutch, or
top of the piston may be
damaged. Also, do not
insert a screw driver or
similar into the exhaust
port.
6
It is recommended to use Crankshaft
Clamp 37 (Code No.71530600) available
as an optional tool.
It is made of durable engineering plastic
and locks the crankshaft without risk of
damage to any part of the engine.
Application is as follows:
Remove the crankcase rear cover plate from
the engine and rotate the crankshaft to the
bottom dead center (BDC) position.
Insert the crankshaft clamp so that its grooved
portion surrounds the crankpin and lower end
of the connecting rod and securely tighten the
fan or clutch onto the crankshaft.
BDC position
Rotate the crankshaft so that the
connecting rod comes to this position.
Insert this groove onto
the connecting rod.
7
NOTES WHEN APPLYING AN ELECTRIC STARTER
Do not over-prime. This could cause
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 pumped
out fuel getting into your eyes.
8
INTRODUCTION
This is a high performance engine
designed for small-sized radiocontrolled helicopters.
Since the mounting bolt pattern of the
engine as well as silencer is the same as
those of the 32SX-H, it can be directly
replaced with the 32SX-H and most of
other 32-39 size engines. This powerful
engine is suitable for sport flight as well
as 3D flight.
With some models, needle interferes the
body and working on the body to avoid
this would be required.
STANDARD ACCESSOIES
Glow Plug No.8
Instruction manual
BEFORE STARTING
Tools, accessories, etc.The following items are
necessary for operating the engine.
Items necessary for starting
Glow Plug
O.S. No.8 is supplied with the engine.
Battery leads
These are used to conduct current
from the battery to the glowplug.
Basically, two leads, with clips, are
required, but, for greater convenience, twin leads with special
glowplug connectors, as shown on
the right, are commercially available.
Glowplug battery
The power source for heating the glowplug may be
either a large heavy-duty 1.5volt dry cell, Ni-cd battery
or glowplug Igniter.
1.5 volt dry cell
9
Battery leads
glowplug Igniter
In case of 1.5volt dry cell
Make sure glowplug element
glows bright red inside room
or shadow.
Hexagon starting shaft
This shaft mounted on an
electric starting motor is driven
into the shaft cup to turn the
engine.
Electric starter and starter
battery
An electric starter is recommended for starting.
Battery leads
12V Battery
Starter
Fuel
Select, by practical tests, the most suitable fuel from
among the best quality fuels available in your country
for helicopter use. For the best throttle response, a
fuel containing 10% to 30% nitromethane is
preferable. Lubricants may be either castor-oil or a
suitable synthetic oil (or . a blend of both) provided
that they are always of top quality. For consistent
performance and long engine life, it is essential to use
fuel containing AT LEAST 18%
lubricant by volume. Some fuels
containing coloring additives tend to
deterriorate and may adversely affect
running qualities. If in doubt compare
to a fuel known to be good.
Reminder!
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.
10
Fuel Pump
Alternatively, one of the purposemade manual or electric fuel pumps
may be used to transfer fuel directly
from your fuel container to the fuel
tank.
O.S. Super Filter (Fuel Can Filter)
Install a filter on the outlet tube of your
refueling container to prevent entry of
foreign matter into fuel tank. O.S. ‘Super
Filters’ (large and small) are available as
optional extras.
Fuel Filter
It is recommended to install a good inline filter between the fuel tank and
carburetor to prevent entry of foreign
matter into the carburetor.
Silicone Fuel Line
Heatproof silicone tubing of approx.
5mm o.d. and 2.5mm i.d. is required
for the connection between the fuel
tank and engine.
Manual
Electric
TOOLS
Hex Driver
Necessary for engine installation.
1.5mm, 2mm, 2.5mm, 3mm
Phillips Screwdrivers
No.1, No.2, etc.
Screwdriver
Necessary for carburetor adjustments.
No.1, No.2, etc
Socket Drivers
5mm, 5.5mm, 7mm
11
LONG SOCKET DRIVER WITH PLUG GRIP
Recommended for easy removal and replacement of
the angled and recessed glowplug, the O.S.Long
Socket Wrench incorporates a special grip.
8mm
End Wrenches
8mm, 13mm, 14mm, etc.
Needle Nose Pliers
12
ENGINE PARTS NAME
Heatsink Head
Carburetor
Typr 20M
Thrust Washer
Propeller nut
Crankshaft
Glowplug
Beam Mount
Crankcase
Rotor Guide Screw
Mixture Control Valve
Fuel Inlet
Cover Plate
Throttle Lever
Needle Valve
Carburetor Gasket
13
FACTS ABOUT GLOWPLUGS
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 No.8, A5 and A3. Carefully install plug finger-tight,
before final tightening with the correct size plug
wrench.
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.
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items.
However, plug life can be extended and engine
performance maintained by careful use, i.e.:
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.
When to replace the glowplug
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
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.
14
INSTALLING
THE GLOWPLUG
Install washer on glowplug and insert carefully into
Heatsink-head, making sure that it is not crossthreaded before tightening firmly.
Glow plug
Washer
INSTALLATION OF THE ENGINE
The under-surfaces of all O.S. engine beam
mounting lugs are precision machined flat and
exactyly parallel to the engine's horizontal axis. It is
essential that the engine mounts in the model are
also accurately made and aligned. If they are not,
they will cause stress and distortion within the engine
itself, probably resulting in loss of performance and
internal damage. The recommended screws for
securing the engine to the engine mounts in the
model are 3mm or 4-40 steel Allen type. It is also
advisable to use lock washers or LOCTITE to prevent
nuts from loosening.
NOTE:
With some models, needle interferes the body
and working on the body to avoid this would be
required.
15
CORRECT
Front view
Top surfaces are in the same plane.
INCORRECT
Top surfaces are not
in the same plane.
Engine does not rest firmly.
Re-align the surfaces as necessary
Side view
Top surfaces are not in
the same plane.
16
CARBURETOR CONTROLS
With a fixed-wing model, power failure is rarely a
serious threat to the safety of the aircraft since it can
usually glide down to a safe landing. In a helicopter,
on the other hand, it is vitally imporant that the engine
keeps running and that there is a quick and reliable
response to the throttle in order to ensure safe ascent
and descent of the model.
Two adjustable controls are provided on this carburetor.
The Needle Valve:
When set to produce maximum power at full throttle,
this establishes the basic fuel/air mixture strength.
This is then maintained by the carburetor's
automatic mixture control system to cover the
engine's requirements at reduced throttle settings.
The Mixture Control Valve
For adjusting the mixture strength at part-throttle
and idling speeds, to obtain steady idling and
smooth acceleration to medium speeds. The Mixture
Control Valve has been factory set for the
approximate best result. First, run the engine as
received, and re-adjust the Mixture Control Valve
only when necessary.
Make sure that only the under-surfaces of the
engine’s mounting lugs are in contact with the
engine mount. Please note that crankcase volume of
the 37SZ-H is a little larger than the 32SX-H’s. If the
crankcase body touches the mount, chamfer the
edges of the mount.
MIxture Control Valve
Needle Valve
REALIGNMENT OF MIXTURE CONTROL VALVE
In the course of making carburetor adjustments, it is
just possible that the Mixture Control Valve may be
inadvertently screwed in or out too far and thereby
moved beyond its effective adjustment range.
Its basic setting can be reestablished as follows :
0.5mm
Carburetor Body
First rotate the Mixture
Control Valve until its
slotted head is flush with
the carburetor body.
Then screw the valve in
exactly 1 turn. This is the
standard position.
Mixture Control Valve
17
Graduations on the carburetor body
Fully opened position
As shown in the sketch, the carburetor has
graduation marks. When the triangle mark on the
carburetor rotor meets the most right mark, throttle is
fully closed. When the triangle mark meets the top
mark, throttle is fully open. The range is approximately
80 degrees. You may use other three marks as the
reference marking of throttle opening to your
preference when hovering.
WARNING!
Never try to check the triangle mark position
while the engine is running and rotor is
rotating, or you may be hit by rotating rotor which
results in serious injury. Stop the engine and
rotor before checking the triangle mark position.
Approx.
Fully closed position
Carburetor Body
Carburetor Rotor
STARTING
Be sure to use a muffler pressurized fuel feed. Use
the same fuel as you intend to employ for actual
operation of your model.
Opening and closing of the Needle-Valve
1.
Turn the needle clockwise to
close the needle-valve, and turn
the needle counter-clockwise to
open the needle-valve as shown
in the sketch.
Opening the needle-valve
2.
Firstly, turn the needle clockwise slowly until it
stops. The position it stops is the fully closed
position of the needle-valve. Make note this
position for reference..
Open the needle-valve 1.5 turns.
Preparation of the starter
3.
Install the starting shaft to the
starter securely. Poor installation
swings the starting shaft, which is
dangerous.
18
Open
Close
Checking the rotating direction of the starter
4.
Make sure that the starter rotates
to the direction shown in the
sketch. If the direction is reverse,
reverse the leads on battery.
Inserting the starter shaft
5.
Insert the starting shaft into the
shaft cup securely.
Priming
6.
Without heating the glowplug, open
the throttle a little from the idle
position. Turn the engine using the
starter until the fuel is seen to reach
carburetor.
7.
Preparation of starting
Make sure that the transmitter
throttle stick is at the fully closed
position and the throttle trim at
center position, and make sure that
idle-up switch on the transmitter is
off. Hold the rotor head by hand so
that rotor cannot rotate when the
engine is Started. Also, steady the
model with a foot on the landinggear skid.
Starting
8.
Connect the battery to the glowplug and start the
engine by applying the starter. When started,
switch off the starter and withdraw the starting
shaft after making sure the rotation of the starter
shaft stops.
Stopping the engine
9.
Fully pull down the throttle trim on the transmitter.
Note:
Make sure that the throttle linkage is
made so that the throttle is fully closed
when the throttle lever as well as trim
lever on the transmitter are fully pulled
down.
In case the engine does not stop.
Hold the rotor head, and pinch the silicone tube to
stop the fuel supply. If it still does not stop, pull off the
fuel tubing from the carburetor.
It is necessary to readjust the throttle linkage so that
the carburetor rotor is fully closed when the throttle
stick and throttle trim on the transmitter are fully
pulled down.
19
NOTE:
If the throttle response is poor or the engine
stops due to a temporarily over-rich mixture immediately after the engine is started, pinch the
fuel line for one or two seconds until the engine
r.p.m. increase and the engine runs steadily.
Reminder!
Never touch, or allow any object to
come into contact with, the rotating
!
rotor.
RUNNING-IN ("Breaking-in")
All internal-combustion engines benefit, to some
degree, from extra care when they are run for the first
few times known as running-in or breaking-in.
This is allows the working parts to mate together
under load at operating temperature.
However, because O.S. engines are made with the
aid of the finest modern precision machinely and from
the best and most suitable materrials, only a very
short and simple running-in procedure is required and
can be carried out with the engine installed in the
modle. For the first few flights with a new engine i.e.
while the engine is being run-in set the needle-valve
for a slightly rich mixture not excessively rich as this
may result in poor throttle response and cause the
engine to stope. About 1.5 turn open from the nomal
setting will usually suffice.
20
ー
ADJUSTMENT
The following adjustments are approximately correct
when using a fuel containing 18-25% lubricant and
10-30% nitromethane.
Bear in mind that fuels containing relatively large
percentages of power-boosting nitromethane operate
at richer mixture settings than are needed for mild
fuels and will, therefore, require the Needle Valve to
be readjusted accordingly. The type and percentage
of lubricant used is also a factor here, as noted later
in these instructions.
This carburetor is not equipped with a throttle
stop screw. Instead, idle speed is adjusted by
means of the throttle trim lever on the transmitter.
This enables the full r.p.m. range, from idling to full
A
power, to be controlled by the throttle stick, and
then allows the engine to be stopped, from the
transmitter, by closing the throttle completely with
the trim lever.
Set up the throttle linkage as follows:
With the transmitter throttle trim lever fully
retarded, adjust the throttle servo linkage so that
the throttle rotor is (a) fully open when the
transmitter throttle stick is fully advanced and (b)
closed (i.e. engine stopped) when the stick is
fully
retarded. The idle speed is then set by
fully
advancing the throttle trim lever to the point where
the engine runs, steadily and reliably,at the
desired idle speed.
As a safety measure, first check the transmitter
B
controls, including the throttle stick and trim lever
positions, and hold the main rotor securely before
starting the engine.
C
Warm the engine by allowing it to idle for about 30
seconds. If the engine stops, advance the throttle
trim lever slightly to increase the idle rpm. Then
open the throttle sufficiently to 'float' the model
above the ground.
21
lf, at this time, the engine is slow to pick up and
D
produces an excess of exhaust smoke, the mixture
is too rich. Correct this condition by turning the
Mixture Control Valve clockwise. lf the mixture is
extremely rich, engine rpm will become unstable :
opening the throttle will produce a great deal of
smoke and rpm may drop suddenly or the engine
may stop. This condition may also be initiated by
an excessively prolonged warming-up period.
lf, on the other hand, the mixture is too Iean, this
E
wiIl be indicated by a marked lack of exhaust
smoke and a tendency for the engine to cut out
when the throttle is opened. ln this case, turn the
Mixture Control Valve counter-clockwise to enrich
the mixture.
Turn the Mixture Control Valve 15 degrees at a
F
time.
Having provisionally set the idle mixture, the next
G
step is to adjust the mixture for hovering flight.
Hover the model and actuate the throttle to
H
observe response over the medium speed range.
lf the engine smokes excessiveIy and throttle
response is poor, the mixture is too rich ; in which
case, land the model and turn the Needle Valve
clockwise. Do not close the NeedIe Valve too
much, keeping it a little on the rich side at this
stage.
lf, on the other hand, hovering is not stable and
I
response to the throttIe is over-sensitive, or if the
engine tends to overheat, this indicates that the
mixture is too lean and should be corrected by
turning the Needle Valve counter-clockwise.
J
When satisfactory hovering flight has been
achieved, land the modeI again and re-check the
engine's idle qualities.
K
After about 10 seconds of idling, open the throttle
to 'float' the model. lf the transition is smooth, the
idle mixture is O.K. If the symptoms of either rich
or Iean running are
Control Screw accordingly.
Now adjust the Needle Valve to achieve the best
L
performance when the model is flying at full
throttle. lf, at full throttle, acceleration is poor, the
observed, readjust the Mixture
22
exhaust unduly smoky and the model fails to reach
expected straight line speed, the mixture is too rich
and the Needle Valve setting will need to be
reduced. lf, however, after smoothly acceIerating
to satisfactory high-speed straight and level flight,
power is lost when the model is puIled up into a
climb, the mixture is too lean. ln this case, land the
model immediately and readjust Needle Valve to a
richer setting.
Now re-check hovering performance and, if
M
necessary, fine-tune the mixture for hovering flight.
N
For helicopters, good throttle response at medium
r.p.m. (e.g.hovering speeds) is most important,
since this is a power range widely used in
helicopter flight. The optimum fuel/air mixture
strength at medium speeds is dependent on
obtaining balanced adjustment of both the Needle
Valve and the Mixture Controlof both the Needle
Valve and the Mixture Control Valve. lf both
controls are already at their optimum setting, some
modification to these settings may be necessary to
achieve satisfactory mid-range throttle response,
but such readjustments should onIy be made
within the range where idle reliability and highspeed performance are not unduly compromised.
Readjustments should therefore be carried out as
follows:
lf the mid-range throttle response is not rapid and
O
positive (indicating a rich mid-range mixture), turn
the Needle Valve 2 or 3 clicks clockwise, or turn the
Mixture Control Valve 1-3 degrees cIockwise.
lf, on the other hand, the response to mid-range
P
throttle movement is too sensitive (indicating a lean
mid-range mixture), turn the Needle Valve 2 or 3
clicks counter-clockwise or turn the Mixture Control
Valve 1-3 degrees counter-clockwise.
Throttle response at hovering speeds is aIso
Q
affected by the reIationship of the main rotor pitch
angle to throttle opening. If the optimum mid-range
throttle response cannot be obtained by the
carburettor adjustments described above, try
adjusting the helicopter's pitch control
characteristics.
23
SUBSEQUENT READJUSTMENTS
Once the engine has been run-in and the carburetor
controls properly set up, it should be unnecessary to
alter the mixture settings, except to make minor
adjustments to the Needle Valve occasionally, to take
account of variations in climatic condisitions.
The use of a different fuel, however, particularly one
containing more, or less, nitromethane and / or a
different type or proportion of lubricating oil, is likely to
call for some readjustment of the Needle-Valve.
Remember that, as a safety measure, it is advisable
to increase the Needle Valve opening by an extra
half-turn counter-clockwise, prior to establishing a
new setting. The same applies if the silencer type is
changed. A different silencer may alter the exhaust
pressure applied to the fuel feed and call for a revised
Needle-Valve setting.
The use of a different glowplug, or changes to the
mainrotor and its pitch angles may also require
compensating carburetor readjustments.
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on
its small fuel orifices remaining clear. The minute
particles of foreign matter that are present in any fuel
can easily partially obstruct these orifices and upset
mixture strength so that engine performance
becomes erratic and unreliable. It is recommended
that fuel is passed through a filter when the tank is
filled and that a good in-line filter is installed between
the fuel tank and carburettor and, furthermore, that
this filter is frequently cleaned to remove dirt and lint
that accumulates on the filter screen. Finally,
occasionally remove the needle-valve holder from the
carburetor as shown in Photo and extract any
remaining foreign matter that may have lodged in the
location shown in right.
Dirt and fbrous matter
mostly accumulate here
24
Remove this with
an 8mm spanner
ADJUSTING CHART
A
Open the Needle Valve 1.5 turns from the fully closed position.
Make sure that the Mixture Control Valve is at the factory setting.
Observe the mixture condition while "floating" the model
E
Open the
Needle Valve
(Turn counter-clockwise)
25
Open the
Needle Valve
(Turn counter-clockwise)
P
Turn the Needle Valve
2 or 3 clicks counterclockwise, or turn the
Mixture Control Valve
10-20 degrees counterclockwise. Adjust pitch
control characteristics.
F
Turn the Mixture
Control Valve
counter-clockwise
I
Turn the Mixture
Control Valve
counter-clockwise
Q
Lean mixture
Lean mixture
K
Idle for approx: 10 seconds, then reopen throttle to
observe transition ("Float" the model)
Lean mixture
Lean mixture
Response too sensitive
B
Start the engine
Warm up the engine
C
Rich mixture
G
Observe the hovering mixture condition
M
Fine tuning of hovering mixture
Idling OK
Hovering OK
J
Land the model
Idle OK
L
High Speed Flight
High Speed Flight OK
N
Hovering OK
Adjustment completed
Rich mixture
Rich mixture
Rich mixture
Response too slow
D
E
Turn the Mixture
Control Valve
clockwise
H
Close the
Needle Valve
(Turn clockwise)
Turn the Mixture
Control Valve
clockwise
Close the
Needle Valve
(Turn clockwise)
O
Q
Turn the Needle Valve
2 or 3 clicks clockwise,
or turn the Mixture
Control Valve 10-20
degrees clockwise.
Adjust pitch control
characteristics.
INSTALLATION OF THROTTLE SERVO
After the engine in the helicopter, please observe
the following recommendations when linking the
throttle servo to the carburetor.
Servo output arm
Throttle arm
Locate the servo so that its output arm and the
throttle pushrod are, as closely as possible, directry
in line with carburetor's throttle arm, as shown.
CARE AND MAINTENANCE
The minute particles of foreign matter, that are
1.
present in any fuel may, by accumulating and
partially obstructing fuel flow, cause engine
performance to become erratic and unreliable.
O.S. 'Super-Filters' (large and small)are available,
as optional extras, to deal with this problem.
One of these filters, installed to the outlet tube
inside your refueling container, will prevent the
entry of foreign material into the fuel tank. It is also
recommended that a good in-line filter be installed
between the tank and carburetor.
Do not forget to clean the filters regularly to remove
2.
dirt and lint that accumulate on the filter screens.
Also, clean the carburetor itself occasionally.
At the end of each operating session, drain out any
3.
fuel that may remain in the fuel tank. Next, energize
the glowplug and try ot restart the engine to burn off
any fuel that may remain inside the engine.
Repeat this procedure until the engine fails to fire.
Remove the glowplug and eject any remaining fuel/oil
residue by rotating the engine with an electric starter
for 4 to 5 seconds while the engine is still warm.
Throttle control rod A and B should be equal of length.
Set the linkage so that the servo output arm and throttle
arm become parallel when the throttle stick on the transmitter is at middle position. If differential throttle movement is required, make necessary adjustment at the
transmitter.
26
Finally, inject some after-run oil into the engine. Rotate
4.
the engine a few times by hand, to make sure that it
is free, and then with an electric starter for 4 to 5
seconds to distribute the oil to all the working parts.
Note:
Do not inject after-run oil into the carburetor as this may
cause the O-rings inside the carburetor to deteriorate.
These procedures will reduce the risk of starting
difficulties and of internal corrosion after a period of
storage.
27
TROUBLE SHOOTING
Cause
Fuel tank is empty.
Fuel not reaching the engine.
Glowplug element is burnt out.
Glowplug battery discharged
Clogged fuel filter
Silencer inside is dirty.
Over priming Remove glowplug and pump excess fuel.
Fill the tank with fuel and repeat
Priming procedure.
Replace glowplug.
Recharge or replace the battery.
Clean or replace fuel filter.
Clean inside silencer.
Symptom
Engine fails to fire.
Corrective action
Fuel tubing is disconnected.
Fuel tubing is kinked, split or has a hole.
Incorrect carburetor settings
Incorrect servo linkage
Reverse rotating direction of electric starter.
Symptom
Engine fires intermittently but does not run.
Cause
Connect fuel tubing securely.
Check the tubing carefully and replace if necessary.
Return the needle valve
and mixture control valve to basic position.
Re-linkage after setting servo at neutral.
Mare sure it rotates counter clockwise seen
from crankshaft side.
28
Corrective action
Insufficient fuel in the tank. Fill the tank with fuel.
Deteriorated glowplug
Clogged fuel filter
Silencer inside is dirty.
Engine overheated
Starting battery disconnected too soon.
Air bubbles in fuel.
Replace glowplug.
Clean or replace fuel filter.
Clean inside silencer.
Wait until engine is cooled.
Do not disconnect plug battery and wait until
r.p.m. become stable.
Mount fuel tank in foam rubber
29
Symptom
Unstable idle
Cause
Corrective action
Unsuitable glowplug
Unsuitable fuel
Silencer is disconnected or is loose
Symptom
Not reaching expected peak r.p.m.
Cause
Insufficient warming up or running-in.
Silencer or manifold is not securely connected
or disconnected.
Fuel tubing from tank to is split or broken.
Use suggested glowplug in the instructions.
Do not use extremely high nitro or low oil fuel.
Install silencer securely.
Corrective action
Set the needle only after warming up.
Complete running-in.
Check the connections and secure them.
Replace the tubing.
30
Symptom
Poor response
Cause
Deteriorated glowplug
Incorrect carburetor settings
Inaccurate linkage
Symptom
Poor r.p.m. drop
Cause
Too much throttle opening at idle.
Incorrect carburetor installation
Needle valve closed too far. Open needle-valve slightly
Replace glowplug.
Readjust low r.p.m. range with metering
needle and mixture control valve.
Recheck the throttle opening against
the pith angle.
Lower the throttle trim to adequate position
to lower idling r.p.m.
Install carburetor securely.
31
Corrective action
Corrective action
ENGINE EXPLODED VIEW
C.M3x15
ENGINE PARTS LIST
1
32
8
N.+M3.5X5
11
10
9
Type of screw C…Cap Screw M…Oval Fillister-Head Screw
＊
F…Flat Head Screw N…Round Head Screw S…Set Screw
0.2mm
2
3
5
4
6
7
13
12
No.
Code No.
1
23414300
2
23413100
3
25403400
4
17
15
33
C.M2.6x7
16
5
6
7
8
9
10
11
12
13
14
15
16
17
23413200
23406000
24517000
23415000
23483000
23210007
22620003
22831000
23411000
23730000
23412000
23424000
23427000
23411300
71608001
14
The specifications are subject to alteration for improvement without notice.
Heatsink Head
Cylinder Liner
Piston Ring
Piston
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete (Type 20M)
Propeller Nut
Thrust Washer
Crankshaft Bearing (Front)
Crankcase
Crankshaft Bearing (Rear)
Crankshaft
Gasket Set
Cover Plate
Screw Set
Glow Plug No.8
Description
CARBURETOR EXPLODED VIEW
C.M3x8
1-1
1
Type of screw
＊
C…Cap Screw M…Oval Fillister-Head Screw
F…Flat Head Screw N…Round Head Screw S…Set Screw
2
N.+M3.5x5
4
5
3
5-3
5-1
5-6
5-4
5-5
5-2
6-2
6-1
7
6
8
34
CARBURETOR PARTS LIST
No.
Code No.
1
1-1
2
3
4
5
5-1
5-2
5-3
5-4
5-5
5-6
6
6-1
6-2
7
8
27381410
22826131
23483200
23483100
45581820
27081900
27981910
24981837
46181940
46181941
26711305
46181950
21285600
46066319
22781800
22615000
23081706
Throttle Lever Assembly
Throttle Lever Retaining Screw (2pcs.)
Carburetor Rotor
Carburetor Body
Rotor Guide Screw
Needle Valve Assembly
Needle Assembly
"O" Ring (2pcs.)
Needle Valve Holder Assembly
Needle Valve Holder
Ratchet Spring
Fuel Inlet (w/Gasket)
Mixture Control Valve Assembly
"O" Ring (L) (2pcs.)
"O" Ring (S) (2pcs.)
Carburetor Rubber Gasket
Carburetor Retaining Screw (2pcs.)
The specifications are subject to alteration for improvement without notice.
Description
35
O.S. GENUINE PARTS & ACCESSORIES
JAPAN
JAPAN
GLOWPLUG
No.8
(71608001)
A3
(71605300)
A5
(71605100)
DRIVE HUB
(23408000)
LONG SOCKET WRENCH
WITH PLUG GRIP
(71521000)
SUPER FILTER
(L)
(72403050)
LOCK WASHER
(10set)
(55500002)
M3
The specifications are subject to alteration for improvement without notice.
CAP SCREW SET
M2.6x7
CRANKSHAFT CLAMP
37
(71530600)
(10pcs.)
(79871020)
36
THREE VIEW DRAWING
SPECIFICATIONS
Displacement
Bore
Stroke
Practical R.P.M.
Power output
Weight
6.07 cc (0.370 cu.in.)
20.5mm (0.806 in.)
18.4mm (0.725 in.)
2,000-21,000 r.p.m.
1.4 ps / 18,000 r.p.m.
293g (10.34 oz.)
42
18
JAPAN
30.6
45
7.57.5
38
50
35
6115.8
1/4-28UNF
N
A
P
A
J
45.9
21.3
30.8
Dimensions(mm)
37
MEMO
38
C
Copyright 2004 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
URL : http://www.os-engines.co.jp
TEL. (06)6702-0225
FAX. (06)6704-2722
60091520 010603
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