O.S. engine Max-50SX-H Ring Setup guide

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.
WARNINGS
ENGINE PARTS NAME
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.
NOTES
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.
Never touch, or allow any object to come
into contact with, the rotating parts.
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.
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.
This engine was designed for model helicopters.
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 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.
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.
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, screwdriv-
ers, 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 accidents.
F
J J
F
28
34
27
33
A
B
90°
90°
A=B
Linking the throttle servo to the carburetor
Link the throttle servo to the carburetor using
the throttle lever supplied. Throttle control rod
A and B should be equal length. Set the
linkage so that the servo output lever and
throttle lever are parallel when the throttle
stick on the transmitter is at middle position.
Installing hole intervals on the F lever and on
the J lever are different. Decide the lever to
use according to the servo used. Be sure to
cut off another lever to avoid any interference.
INTRODUCTION
600928900000
Note on heating the glow plug
Example
The heatsink head on the engine is treated with
an anodized finish which does not conduct
current. Therefore, when heating a glow plug,
connect one lead to the glow plug and the other
to the head or cover plate retaining screw.
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.
Heatsink Head
Carburetor
Typr 60LH
Crankshaft
Propeller nut
Crankcase
Glowplug
Beam Mount
Needle Valve
Fuel Inlet
Mixture Control
Valve
Throttle Lever
Mixture Control Screw
Mixture Control
Valve Stopper
Thrust Washer
Carburetor
Rubber Gasket
Cover Plate
This is the increased power version of the 50SX-H
RING whis is developed expressly for F3C M class
helicopter competition utilizing 0.50 cubic inch
engines.
Blue Alumite heatsink head increases cooling
capacity. Newly designed combustion chamber
shape offers stable output both at hovering and
high speed. The 60LH caburetor has a big 10mm
bore which contributes the power increase.
When the governor function from Futaba GY-701 or
GY-750 gyro is employed, the Futaba BPS-1 Back
Plate Sensor can be installed in a cell on the back
plate. By employing the governor function, more
stable flight can be achieved.
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 the similar
into the exhaust port.
Do not grip the engine mounting beams with a
vise, or the crankcase will be distorted which
will result in engine breaking.
Vise
NOTES WHEN APPLYING AN ELECTRIC STARTER
Because of this initial tightness, a standard
electric starter may have difficulty in rotating the
engine when cold, before it has been adequately
run-in. In this case, use a high-torque type 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 pumped out fuel
from getting into your eyes.
Beam Mount
It is recommended to use
Crankshaft Clamp 3246
(CodeNo.71530400) available
as an optional tool.
Carburetor
Sealing Washer
MAX-50SX-H RING Hyper

Items necessary for starting
Tools, accessories, etc.The following items are necessary
for operating the engine.
BEFORE STARTING
Fuel
INSTALLATION OF THE ENGINE
Make sure that only the under-surfaces
of the engine’s mounting lugs are in
contact with the engine mount.
INSTALLING THE GLOWPLUG
Install washer on glowplug and insert carefully into
Heatsink-head, making sure that it is not cross-threaded
before tightening firmly.
INSTALLATION OF THE CARBURETOR
CARBURETOR CONTROLS
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.
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.
Retainer screw
Carburetor Rubber Gasket
0.2mm gap
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.
BASIC POSITION OF MIXTURE CONTROL SCREW
(Mixture Control Valve)
Rich
Mixture Control Valve
MIxture Control Screw
Lean
As delivered, the Mixture Control Screw is positioned at
approximately the center as shown in the sketch.
Mixture gets lean when the Mixture Control Screw is
turned right, while mixture gets rich when the Mixture
Control Screw is turned left.With a model helicopter,
adjustments vary with combined various factors such as
climatic conditions, fuel, muffler, main rotor, weight of
the model, gear ratio, etc. Therefore the Mixture Control
Screw position varies with each model and set- up, and
it is normal if the Mixture Control Screw position is off
the center.
When the triangle mark on the carburetor rotor meets
the far right mark, the throttle is fully closed.
When the triangle mark meets the top mark, the throttle
is fully open. The range is 86 degrees. You may use the
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.
As shown in the sketch, the carburetor has graduation
marks.
GRADUATIONS ON THE CARBURETOR BODY
Battery leads
1.5 volt dry cell
These are used to conduct current from
the battery to the glowplug. Basically, two
leads, with clips, are required, but, for
greater conve-nience, twin leads with
special glowplug connectors, as shown on
the right, are commercially available.
Battery leads
glowplug Igniter
The power source for heating the glowplug may be
either a large heavy-duty 1.5volt dry cell, Ni-cd battery
or glowplug Igniter.
Glowplug battery
Make sure glowplug element glows
bright red inside room or shadow.
Battery leads
In case of 1.5volt dry cell
12V Battery
Starter
Electric starter and starter battery
An electric starter is recommended
for starting.
Hexagon starting shaft
This shaft mounted on an electric starting motor
is driven into the shaft cup to turn the engine.
Alternatively, one of the purpose-made
manual or electric fuel pumps may be
used to transfer fuel directly from your fuel
container to the fuel tank.
Manual
Electric
It is recommended to install a good
in-line filter between the fuel tank and
carburetor to prevent entry of foreign
matter into the carburetor.
Fuel Filter
Fuel Pump
Silicone Fuel Line
TOOLS
Screwdriver
Necessary for engine installation.
1.5mm, 2mm, 2.5mm, 3mm
Necessary for carburetor adjustments.
No.1, No.2, etc
Phillips Screwdriver
No.1, No.2, etc.
Socket Drivers
5mm, 5.5mm, 7mm
Hex Drivers
Install a filter to 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.
O.S. Super Filter (Fuel Can Filter)
Heatproof silicone tubing of approx. 5mm o.d.
and 2.5mm i.d. is required for the connection
between the fuel tank and engine.
O.S. SPEED PLUG WRENCH
(optional extra)
Loosen the retainer screw, rotate the carburetor to its
correct position and press it well down into the intake
boss, compressing the rubber gasket as shown in the
sketch, before re-tightening screw.
Rotate the retainer screw gently until it stops, then
tighten a further 90-120 degrees. Do not over-tighten
the screw as this will damage the carburetor body.
1.
2.
MIxture Control Screw
Needle Valve
As the idle mixture control screw is installed
with LOCTITE, it may initialy feel stiff, and it is
suggested to use a slightly oversized
screwdriver. The screw can be turned only 90
degrees either way. Do not force to turn
further, or it may break or cause trouble.
NOTE
90 degrees
90 degrees
Be sure to use an electric starter to start the engine.
Fill the fuel tank with fuel. When filled, prevent the
fuel from flowing into the carburetor with a
commercially available fuel stopper, etc.
Release the stopper before starting the engine.
1.
2.
Starting procedure is as follows:
Make sure that plug element glows red, and install
the plug in the cylinder head.
STARTING
Open
1.
2.
Opening and closing of the Needle-Valve
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.
Close
4. Checking the rotating direction of the starter
3. Preparation of the starter
Be sure to use a muffler pressurized fuel feed.
Use the same fuel as you intend to employ for
actual operation of your model.
Make sure that the starter rotates
to the direction shown in the
sketch. If the direction is reverse,
reverse the leads on battery.
Install the starting shaft to the
starter securely.
Improper installation will allow the
shaft to swing creating a dangerous
situation.
Please note that crankcase volume of the
50SX-H is a little larger than the 46FX-H’s.
If the crankcase body touches the mount,
chamfer the edges of the mount.
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 ControlScrew (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.
Two adjustable controls are provided on this carburetor.
Carburetor Rotor
Carburetor Body
Fully closed position
Fully opened position
Opening the needle-valve
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.

RUNNING-IN ("Breaking-in")
ADJUSTMENT
CARE AND MAINTENANCE
Please pay attention to the matters described
below to ensure that your engine serves you well
in regard to performance, reliability and long life.
As previously mentioned, it is vitally important to
avoid operating the engine in conditions where dust,
disturbed by the propeller, may be deposited on the
engine and enter its working parts.
Remember to keep your fuel container closed to
prevent foreign matter from contaminating the fuel.
Install a fuel filter to prevent foreign matter in the fuel
container from entering the fuel tank. O.S. Super
Filters (L) and (S) are available as optional extras.
Install an in-line fuel filter between the tank and
carburetor to prevent foreign matter in the tank from
entering the carburetor.
If these precautions are neglected, restriction of fuel
flow may cause the engine to cut out, or the fuel/air
mixture to become too lean causing the engine to
overheat.
Clean these filters periodically.
The use of modern high-performance alcohol based
model engine fuels, while promoting cooler running,
improved anti-detonation combustion and increased
power, have the disadvantage of causing corrosion
due to the acid by-products of combustion.
The use of nitromethane in the fuel can also
contribute to the problem.
Do not close the needle-valve and mixture control
valve too far as this will cause a lean setting and
over heating of the engine. This can, in turn, create
nitromethane oxide leading to internal rusting of the
engine. Always adjust the needlevalve slightly on the
rich side of peak rpm.
Do not leave unused fuel in the engine at the
conclusion of a day’s flying. Accepted practice is to
cut off the fuel supply while the engine is still running
at full throttle, then expel as much fuel residue as
possible by turning the engine over 5-10 seconds
with the electric starter.
Finally, inject some after-run oil through the glowplug
hole and turn the engine over several times by hand.
Stopping the engine
Fully pull down the throttle trim on the transmitter.
Starting
Preparation of starting
7.
8.
9.
In case the engine does not stop.
Hold the rotor head, and pinch the fuel line to stop the
fuel supply. If it still does not stop, pull off the fuel line
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.
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.
SUBSEQUENT READJUSTMENTS
CARBURETOR CLEANLINESS
Remove this with
an 8mm wrench
Dirt and foreign matter
mostly accumulate here
6. Priming
5. Inserting the starter shaft
Insert the starting shaft into the shaft
cup securely.
Without energizing the glowplug,
open the throttle a little from the idle
position. Turn the engine over using
the starter until the fuel is seen to
reach the carburetor.
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.
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 landing gear skid.
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.
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 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 model.
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 stop.
About 1.5 turn open from the nomal setting will usually
suffice.
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 idle to full
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.
As a safety measure, first check the transmitter
controls, including the throttle stick and trim lever
positions, and hold the main rotor securely before
starting the engine.
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.
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) fully
closed (i.e.
engine stopped) when the stick is fully
retarded. The
idle speed is then set by advancing the throttle trim
lever to the point where the engine runs, steadily
and reliably,at the desired idle speed.
lf, at this time, the engine is slow to pick up and produces
an excess of exhaust smoke, the mixture is too rich.
Correct this condition by turning the Mixture Control
Screw 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 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 Screw
counter-clockwise to enrich the mixture.
Turn the Mixture Control Screw 5 degrees at a time.
Hover the model and actuate the throttle to 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
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.
Having provisionally set the idle mixture, the next
step is to adjust the mixture for hovering flight.
When satisfactory hovering flight has been achieved,
land the modeI again and re-check the engine's idle
qualities.
Now adjust the Needle Valve to achieve the best
performance when the model is flying at full throttle.
lf, at full throttle, acceleration is poor, the 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.
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 observed, readjust the Mixture Control
Screw accordingly.
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 Control.
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 high-speed performance
are not unduly compromised. Readjustments should
therefore be carried out as follows:
Now re-check hovering performance and, if necessary,
fine-tune the mixture for hovering flight.
lf the mid-range throttle response is not rapid and
positive (indicating a rich mid-range mixture), turn the
Needle Valve 2 or 3 clicks clockwise, or turn the Mixture
Control Screw 1-3 degrees cIockwise.
lf, on the other hand, the response to mid-range
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 Screw
1-3 degrees counter-clockwise.
Throttle response at hovering speeds is aIso 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.
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 carburetor and, furthermore, that this filter is
frequently cleaned to remove foreign matter 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
Photo, right.
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 conditions.
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.

Dimensions (mm)
THREE VIEW DRAWING
ENGINE EXPLODED VIEW ENGINEN PARTS LIST
Type of screw
C…Cap Screw
The specifications are subject to alteration for improvement without notice.
CARBURETOR PARTS LIST
CARBURETOR EXPLODED VIEW
(55500002)
(71605100)
(71608001)
(71607100)
C121401
Copyright 2013 by O.S. Engine Mfg. Co., Ltd. All rights reserved. Printed in CHINA.
http://www.os-engines.co.jp
6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
TEL. [phone]
FAX. [phone]
O.S. GENUINE PARTS & ACCESSORIES
(72403050)
(71531000)
(L)
NON-BUBBLE WEIGHT
SUPER FILTER
M3
LOCK WASHER (10set)
GLOWPLUG
No.10 (Former A5)
No.8
No.7
When the engine is not to be used for some months
(for example, as between flying seasons), a worthwhile
precaution is to remove it from the airframe and, after
washing off the exterior with alcohol (not gasoline nor
kerosene), remove carefully the carburetor with intake
pipe, glow plug and all silicone tubing and put them
safely aside. Then, immerse the engine in a container
of alcohol. Rotate the crankshaft while the engine is
immersed. If foreign matter is visible in the alcohol,
rinse the engine again in clean alcohol. Finally, shake
off and dry the alcohol, and inject some after-run oil in
the glowplug hole and rotate the crankshaft several
times by hand. Reinstall the carburetor with intake pipe
and glowplug on the engine and keep it in a dry place
after putting in a vinyl bag.
POWERBOOST PIPE 55
POWERBOOST PIPE 55
3246
CRANKSHAFT CLAMP
(71531010)
(S)
NON-BUBBLE WEIGHT
(71520100)
O.S. SPEED RACING TOOLS SETS
O.S. SPEED PLUG WRENCH
(71520100)
The specifications are subject to alteration for improvement without notice.
Type of screw
C…Cap Screw
The specifications are subject to alteration for improvement without notice.
(71530400)
(72144000)
(72147000)
Hyper Head
Cylinder Liner
Piston Ring
Piston
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete 60LH
Propeller Nut
Thrust Washer
Crankshaft Bearing (Front)
Carburetor Retainer Assembly
Crankcase
Crankshaft Bearing (Rear)
Crankshaft
Gasket Set
Cover Plate
Screw Set
Glow Plug No.8
No. Description
Code No.
No. Description
Code No.
C.M3x15
C.M2.6x18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
C.M3x8
17
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
25204200
25203100
25303400
25203200
25206000
25217000
25205000
29083020
23210007
46120000
26731002
23981700
25201000
25830000
25202000
25214000
25207001
25613000
71608001
C.M3X8
1-1
12
4
5
6
3-3
10
8
3
3-1
3-2
7
9
9-1
9-3
9-2
9-4
11
1
1-1
2
3
3-1
3-2
3-3
4
5
6
7
8
9
9-1
9-2
9-3
9-4
10
11
29085140
22826131
29083200
29083600
27881810
27881800
27881820
45581820
29083110
22681953
27881330
27681340
27981900
27981910
24981837
27381940
26711305
29015019
23818190
Throttle Lever Assembly
Throttle Lever Retaining Screw
Carburetor Rotor
Mixture Control Valve Assembly
"O" Ring (L) (2pcs.)
"O" Ring (S) (2pcs.)
"O" Ring (L) (2pcs.)
Rotor Guide Screw
Carburetor Body
Fuel Inlet (No.1)
Mixture Control Screw
Mixture Control Valve Stopper Assembly
Needle Valve Assembly
Needle Assembly
"O" Ring (2pcs.)
Needle Valve Holder Assembly
Ratchet Spring
Carburetor Rubber Gasket
Carburetor Sealing Washer
Please note that this engine is not supplied with Drive Hub.
NOTE:
UNF1/4-28
52
36
38 31
26.8
18.3
60.7 25
74
37.7
11
37
51.6
44
17.5
54
47
Displacement
Bore
Stroke
Output
Practical R.P.M.
Weight (Engine)
SPECIFICATIONS
8.17 cc / 0.499 cu.in.
22.0 mm / 0.866 in.
21.5 mm / 0.847 in.
1.9 ps / 1.87 hp / 17,000 r.p.m.
2,000-20,000 r.p.m.
406g / 14.33 oz.