BASIC ENGINE PARTS

O.S. SPEED T1204 W/12F5(B)It is of vital importance, before attempting to operate yourengine, 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 withthe controls and other features of the engine.

SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE

Remember that your engine is not a " toy ", but ahighly efficient internal-combustion machine whose
power is capable of harming you, or others, if it ismisused or abused. As owner, you, alone, areresponsible for the safe operation of your engine, so
act with discretion and care at all times. If at somefuture date, your O.S. engine is acquired by anotherperson, we would respectfully request that these
instructions are also passed on to its new owner.
The advice which follows is grouped under twoheadings 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.

NOTES

These cover the many other possibilities, generally lessobvious sources of danger, but which, under certain
circumstances, may also cause damage or injury.
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 slighttaper. The piston and cylinder are designed toachieve a perfect running clearance when theyreach operating temperature.
Near TDC

CylinderLiner

PistonCrankshaft
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 ahydraulic 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 toprevent any pumped out fuel from getting into
your eyes.

Outer HeadModel engine fuel is poisonous. Do notallow 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.

Install an effective silencer (muffler). Frequent close
exposure to a noisy exhaust (especially in the caseof the more powerful highspeed engines) may
eventually impair your hearing and such noise isalso likely to cause annoyance to others over a wide
area.

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.

Take care that the glowplug clip or battery leads do
not come into contact with rotating parts. Also checkthat the linkage to the throttle arm is secure.

WARNINGS

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 inan open area.

NOTES

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.
NOTES ON OPERATIONABOUT THE WARRANTY
Since this is a special SPEED version, individual
special parts are available only for limited period(one year after finishing the production).
Also, the engine is free of warranty due to damage
and/or wear occurred during running.
While Operating
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 smallchildren.
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.

NOTE
As delivered, the engine has the carburetor
lightly fit into its intake. Secure it changing its
angle according to the car chassis.
ABOUT THE ENGINE

O.S. SPEED T1204 is designed to clear the IFMAR
regulations for 1/10 touring car category.
The new crankshaft has two weights made oftungsten in the counterweight to improve torque in
middle range.
The inner head is sealed by an o-ring to prevent
dust from going into the combustion chamber.
Fin pitch of the outer head is widened for better
cooling.

The Metering Needle:
For adjusting idle and acceleration feeling.
Ball Link[Standard Position]
Flush with the Slide Valve body.

Carburetor
ExhaustThe wearing of safety glasses is also strongly
recommended.

Cover Plate
Crankcase

Crankshaft

To stop the engine, fully retard the throttle stick andtrim 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.
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the engine.
Items necessary for starting

FUEL
Generally, it is suggested that the user selects a fuel that iscommercially available for model two-stroke engines Whenthe 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 notethat with high-nitro fuels, although power
may be increased for competition purposes,
glowplug elements do not last as long andengine life will be shortened.

INSTALLATION OF THE STANDARD ACCESSORIES

Installing the glow plug. Insert RP6 plug supplied intoheatsink-head carefully, making sure that it is notcross-threaded before tightening firmly.
(All the O.S. T-Type plugs including the RP6 are notsupplied with a washer.)
Install the exhaust seal ring
supplied.

ExhaustSeal RingCARBURETOR CONTROLS STANDARD POSITIONS(POSITIONS WHEN THE ENGINE LEAVES THE FACTORY)
Four adjustable controls are provided on thiscarburetor.
Carburetor Reducer
Needle ValveGLOWPLUG IGNITER
Commercialy available handy glowplug
heater in which the glowplug battery andbattery leads are integrated.

The Needle-Valve:
For adjusting air/fuel ratio (air-fuel mixture) at maximum
rpm (fully opened throttle).

STARTER BOX
For starting the engine.

Close(Clockwise)

TOOLS (optional extra)
O.S. SPEED PISTON PIN RETAINER PLIERS
O.S. SPEED DRIVER TOOLS

Needle Valve

Open(Counter-clockwise)[Standard Position]

2.5 turns opened from the fully closed position.

[Fully closed position]

Turn the needle-valve clockwise until it stops.
This is the fully closed position.
Do not force it to turn further.

Standard accessories
The Mixture Control Valve:
For adjusting acceleration feeling.
(Adjusting range should be within ±1 turn.)

Glow Plug RP6
T-type head (Turbo head) 1piece[Standard Position]
Exhaust Seal Ring 1piece

O.S. SPEED FLYWHEEL KEY

Flush with the carburetor body.

Dust Cap Set
3mm 1piece

O.S. SPEED
CLUTCH WRENCH & ADJUSTER

Mixture Control Valve

16mm 2pcs.

O.S. SPEED FLYWHEEL PULLER
O.S. SPEED PLUG WRENCH

Carburetor Body

The following procedure is suitable when a fuelcontaining 20% nitro-methane is used.
1. Set the carburetor controls at the standard positions(positions when the engine leaves the factory.)
2. Switch the transmitter and make sure that eachlinkage moves correctly.

Carburetor Body Slide Valve
Note:
Sketch shows the carburetor reducer removed.
NOTE: While the Mixture Control Valve and theMetering Valve are set at the standard position
when the engine leaves the factory, readjustment
may be necessary, occasionally to allow forchanges 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 installedin the intake boss. Secure it as follows.
Rotate the retainer screw
gently until it stops.
Tighten a further
120-180

Dust CoverBall Link
Metering Needle
Throttle Stop
Mixture Control Valve
Screw
Themo Insulator

O.S. SPEED SILICONE FUEL LINE (optional extra)
The connection between the fuel tank and the engine.
2.5mm ID

[Standard Position]
Approx 0.5mm

Crankshaft Bearing (Front)

FUEL FILTER
To installed in the fuel line between fueltank 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.

PRESSURIZED FUEL SYSTEM
It is recommended that a muffler pressurized fuelfeed system be used so that the fuel may be stably
fed to the carburetor.

The Throttle Stop Screw:
For setting the minimum idle speed:

Mounting Lugs

For their safety, keep all onlookers (especially smallchildren) well back (at least 20 feet or 6 meters)
when preparing your model for running.
Before starting the engine, always check thetightness of all the screws and nuts especially thoseof joint and movable parts such as throttle arm.
Missing retightening the loose screws and nuts
often causes the parts breakage that is capable ofharming you.

Metering Needle
Slide Valve
Carburetor Body

STARTING THE ENGINE & RUNNING-IN ('Breaking-in)

Running- in is a procedure for an engine to comeclose 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 resultin the oil in the fuel becoming gelled and thepiston/liner becoming stuck together.

Pull out
Retaining
Screw"O" Ring"O" Ring
1. Loosen the retainer screw, rotate the carburetor to its
correct position and make sure that it is pressed welldown into the intake boss, compressing the rubber
gasket, before retightening screw.
2. Rotate the retaining screw gently until it stops, thentighten a further 120-180 , and no more.
Do not overtighten the screw as this will damage thethermo insulator.
Note
Be careful not to damage the O rings whenremoving the carburetor retainer from the engine.
First, remove the Retaining screw, then pull out
each retainer. Do not push the retainers in or the O
rings will get damage.
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 existingholes in the engine mount do not align perfectly withengine mounting lugs, enlarge them slightly with aneedle-file so that screws are in alignment with themounting holes.

Do not allow bottomof crankcase totouch chassis.

Chamfer inside edges of bearers.

3. Make sure rotating direction of the starter box iscorrect (counter-clockwise seen from the front edgeof the crankshaft), and turn the engine with thestarter box to draw fuel into the engine.
4. Connect glowplug battery lead to heat the plug andstart the engine with the starter box.
When the engine does not start or stops right after
being started, try the followings.
Set the needle-valve approx. 2 turns open from thefully closed position. Do not force the needlevalve toturn beyond a lightly closed position.
Set the throttle opening a little approx 1mm
wider (approx. 1mm) than thestandard setting by adjusting
the Throttle Stop Screw.

5. When the engine starts, warm it up by repeatedly
increasing the rpm to medium speed and backagain 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.

Attention:
It is vitally important to set thethrottle 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 theground) it will rapidly over-heat and may beseriously damaged.
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 ataround mid speed, the mixture is too rich. Close theneedle-valve 15°.
If the engine still stalls, close the metering needle
15°. Run the car on the track until one tank of fuelhas been consumed, then close the needle-valve
very little (within 10°).
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.
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.
How to stop the engine
To stop the engine, close thethrottle to idle speed and shut it offcompletely with the trim lever on thetransmitter then cut off the fuelsupply by pinching the fuel delivery
tube to the carburetor.

Warning!
Do not touch rotating parts, engine
and silencer when stopping theengine as they become very hot,and contact with them may resultin a serious burn.

FuelLess fuelOpen

More fuel

Close

Less fuel1. NEEDLE VALVE ADJUSTMENT
Run the vehicle (with throttle fully open) over the
longest available straight course a few times toobserve the model’s speed. Return the vehicle to thestarting point and close the Needle-valve 15°and
repeat the run, taking note of the improvement in
performance.
Continue with further runs, gradually reduce the
Needle-valve setting aiming to achieve the highest
straight-line speed (optimum position).
Remember, however, if the Needle-valve is closed too
far, the engine will overheat, accompanied by visibly
diminished exhaust smoke and the model will lose
speed. At this point, throttle down immediately, stopthe vehicle and reopen the Needle-valve 15°.
2. METERING NEEDLE ADJUSTMENT
After setting the Needle-valve at optimum position,
run the vehicle a few times at the straightway, andstop the vehicle. With the engine still running, close
the throttle and allow it idle for about five seconds,
then reopen the throttle fully.
If, at this point, the engine puffs out an excessive
amount of smoke and the vehicle does not
accelerate smoothly and rapidly or even stops, it isprobable that the idle mixture is too rich. In thiscase, turn the Metering needle clockwise 15°.
If, on the other hand, the engine tends to speed up
momentarily with little smoke and then cut out
abruptly when the throttle is opened, the idle
mixture is too lean. In this case, turn the Metering
needle counter-clockwise 15°.

3. THROTTLE STOP SCREW ADJUSTMENT
If the engine runs too fast with the throttle closed, thethrottle stop screw should be turned counter-clockwise
to allow the throttle opening to be reduced.
OPTIMUM MIXTURE CONTROL POSITION
With the optimum mixture control position, light smoke
is visible during high speed running and the engine rpm
increase smoothly during acceleration. Carry out
adjustment 1.~3. patiently until the engine responds
quickly and positively to the throttle control.
Remember that, if the engine is operated with the fuel/air
mixture slightly too lean, it will overheat and run
unevenly. As with all engines, it is advisable to set boththe needle-valve and metering needle slightly on the richside of the best rpm setting, as a safety measure.
Finally, beyond the normal break-in period, a slight
readjustment toward a leaner needle setting may berequired to maintain maximum performance.
Note:
Please regard the standard positions in the
instruction manual as just a guide. Positions willvary due to the fuel and silencer used. In general,
if a fuel containing less nitromenthane is used, theneedlevalve will need to be closed further.
Remember, closing the needlevalve too far cancause rusting and damage to the engine.
CARE AND MAINTENANCE
1. The minute particles of foreign matter, that are present inany 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 pickup tube inside
your refueling container, will prevent the entry of foreignmaterial into the fuel tank. It is also recommended that agood in-line filter be installed between the tank andcarburetor.
2. Do not forget to clean the filters regularly to remove
dirt and lint that accumulate on the filter screens.
Also, clean the carburetor itself occasionally.

4. Then, inject some after-run oil into the engine, androtate the engine 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 todeteriorate. These procedures will reduce the risksof starting difficulties or corrosion after a period ofstorage.
5. Finally, when cleaning the exterior of the engine, use
methanol or a household cleaning agent. Do not use
gasoline, kerosene, or any petroleum based
chemical which can damage silicone fuel tubing.
Note:
Crankshaft of this engine is filled with silicone.
Do not use light oil nor kerosene, etc. forwashing, or the silicone will swell. Use alcoholor fuel for washing and dry it completely.

Dirt and dust may lodge inmarked places.

Type of screw

PRESSURE CHAMBER SET(71550000)

1

INDUCTION SILENCER(72414000)
Induction Silencer Filter (3pcs.)(72414100)

2

ON-ROAD FILTER OIL (20ml)(72414200)

2-1

O.S. SPEED CLUTCH BEARING (1050ZZ 4pcs.)(71550001)

3

O.S. SPEED CLUTCH BEARING (1050ZZ 10pcs.)(71550002)

4
4-1

O.S. SPEED CILICONE TUBE
(72506100) ID. 2.5mm x Length 1000mm
O.S. SPEED EXHAUST SEAL RING 12 (10pcs.)(21427210)

4-2
5

O.S. SPEED FLYWHEEL COLETTE (2pcs.)(71801110)

O.S. SPEED CLUTCH WRENCH & ADJUSTER(71415300)

CHECKING THE ENGINE

If the engine will not develop normal performance after
long time running due to wearing of parts. It is suggested
to replace necessary parts when the following symptoms
are detected.
Engine sound changes and easily overheats.
Power has dropped extremely.
Idle is unstable and/or engine tends to stop at idle.
In most cases, ball bearings, cylinder & piston assembly,
connecting rod and/or crankcase have become worn.
Check the parts carefully and replace them if necessary.
O.S. GENUINE PARTS & ACCESSORIES
O.S. GLOW PLUG
RP6 (71642060)

RP7 (71642070)

TT01 EFRA2672 (T-1070SC L52)
TUNED SILENCER COMPLETE SET(72107600)
TT01 EFRA2672 (T-1070SC L52)
Tuned Silencer Assembly (72107610)
Joint Spring (3pcs.)(72106042)
Exhaust Seal Ring (2pcs.)(22826140)

MT01(M1006SC) Exhaust Header Pipe Assembly(72107620)
Header Pipe Spring (2pcs.)(72106172)
Exhaust Seal Ring (2pcs.)(21427200)
MT03 EXHAUST HEADER POPE ASSEMBLY(72106550)
Header Pipe Spring (2pcs.)(72106172)
Exhaust Seal Ring (2pcs.)(21427200)

4-4

C.M2.6x7

C.M2.6x15

11

DUST CAP SET 3mm (5pcs.)(73300305)

O.S. SPEED PISTON PIN RETAINER PLIERS(71492000)

INATALLING DUST CAPS
When storing the engine, install the cap on the exhaust
port, carburetor, etc. to prevent dust from entering theengine.

4-3

4-3

6

O.S. SPEED PLUG WRENCH(71520100)
O.S. SPEED SPRING REMOVER(71415500)

8CARBURETOR PARTS LIST

S...Set Screw

2-1

2-2

2

3-1
2-3
2-4

4
4-1

1-1
1-2
1

Description

6

7
7-1

5

8
5-1

Description

Code No.

3

3-1

O.S. SPEED DRIVER TOOLS

71414015 O.S. SPEED HEX WRENCH TIP ONLY 1.5
71414020 O.S. SPEED HEX WRENCH TIP ONLY 2.0
71414025 O.S. SPEED HEX WRENCH TIP ONLY 2.5
71414030 O.S. SPEED HEX WRENCH TIP ONLY 3.0
71414120 O.S. SPEED HEX BALL WRENCH TIP ONLY 2.0
71414125 O.S. SPEED HEX BALL WRENCH TIP ONLY 2.5
71414230 O.S. SPEED FLAT HEAD SCREWDRIVER TIP 3.0
71414355 O.S. SPEED NUT DRIVER TIP ONLY 5.5
71414360 O.S. SPEED NUT DRIVER TIP ONLY 6.0
71414370 O.S. SPEED NUT DRIVER TIP ONLY 7.0

No.
1
1-1
1-2
2
2-1
2-2
2-3
2-4
3
3-1
4
4-1
5
5-1
6
7
7-1
8
9
9-1
10

Type of screw

O.S. SPEED PHILLIPS SCREW DRIVER
No.2 (71417200)

O.S. SPEED HEX WRENCH DRIVER 1.5
O.S. SPEED HEX WRENCH DRIVER 2.0
O.S. SPEED HEX WRENCH DRIVER 2.5
O.S. SPEED HEX WRENCH DRIVER 3.0
O.S. SPEED HEX BALL WRENCH DRIVER 2.0
O.S. SPEED HEX BALL WRENCH DRIVER 2.5
O.S. SPEED FLAT HEAD SCREWDRIVER 3.0
O.S. SPEED NUT DRIVER 5.5
O.S. SPEED NUT DRIVER 6.0
O.S. SPEED NUT DRIVER 7.0

Pcs. used in an engine

CARBURETOR EXPLODED VIEW

O.S. SPEED PHILLIPS SCREW DRIVER
No.1 (71417100)

Code No.

Size

9
9-1

10

S.M3x3

THREE VIEW DRAWING

Description
Outer HeadInner HeadInner Head "O" Ring
Head Gasket Set (0.1mm, 0.15mm)
Built-Up Parts Set
Cylinder & Piston Assembly
Piston Pin
O.S.SPEED Piston Pin Retainer 2 (6pcs.)
Connecting Rod (w/piston pin retainers 2 3pcs.)
Carburetor Complete (Type 12F5(B))
Carburetor Retainer Assembly"O" Ring (2pcs.)
Ball Bearing (F)Crankcase
Ceramic Bearing (R)Crankshaft"O" Ring (1pc.)
Cover Plate
Glow Plug RP6
Exhaust Seal Ring (2pcs.)
Dust Cap Set (3mmx1,16mmx2)

79871020 M2.6x7 Cover Plate Retaining Screw (4pcs.)
79871050 M2.6x15 Carburetor Retainer Retaining Screw (1pc.)
79871150 M3x15 Cylinder Head Retaining Screw (4pcs.)

6-1

O.S. SPEED BODY REAMER(71415400)

71410150
71410200
71410250
71410300
71411200
71411250
71412300
71413550
71413600
71413700

Code No.

9

7

Code No.
2CS04000
2CS04100
2CS04180
2A404160
2CS03010
2BS03000
21656000
2AP17000
2A405001
2BS81000
21538170
24881824
21630500
2CS01000
21931100
2CS02000
21921800
2BS07000
71642060
21427200
21682950

Items marked * are available for only limited time.
(One year after discontinuing the production)

CAP SCREW SETS (10pcs./set)

O.S. SPEED FLYWHEEL KEY(71415200)
O.S. SPEED FLYWHEEL PULLER(71415100)

12

10

DUST CAP SET 12-30 (3mmx2,16mmx2,18mmx1)(22884254)

Dirt and stain stuck on the engine and silencer/manifold
cause lowering heat dissipation effect. When dirt andstain are detected, remove the engine from the chassis
and clean it with alcohol.

No.
1
2
2-1
3
4
4-1
4-2
4-3
4-4
5
6
6-1
7
8
9
10
11
12

C.M3x15

C...Cap Screw

DUST CAP SET 16mm (3pcs.)(73301612)

REMOVING DIRT/STAINENGINE PARTS LIST

Code No.
21682600
27881820
22781800
2AP11000
21538900
27881820
21682940
2AP81950
71533455
22615000
21982620
22781800
2BS8110021982900
2A481200
21682510
22781800
21982520
23818430
26381501
22615000

Description
Mixture Control Valve Assembly"O" Ring (L) (2pcs.)"O" Ring (S) (2pcs.)
Needle Valve Assembly
Needle"O" Ring (2pcs.)
Needle Hoolder
No.21 Universal Nipple Assembly
Carburetor Reducer (5.5mm Red) AL2"O" Ring (1pc.)
Throttle Stop Screw"O" Ring (S) (2pcs.)
Carburetor Body (w/Thermo Insulator)
Thermo Insulator
Slide Valve
Metering Needle Assembly"O" Ring (S) (2pcs.)
Dust CoverBall Link No.5
Set Screw
Carburetor Rubber Gasket

Dimensions (mm)SPECIFICATIONS
Displacement
Bore
StrokeOutputPractical R.P.M.
Weight2.10 cc / 0.128 cu.in.
13.67 mm / 0.538 in.
14.3 mm / 0.563 in.
1.75 ps / 1.73 hp / 35,000 r.p.m.
5,000-45,000 r.p.m.
233 g / 8.22 oz. (Engine)

31.4

More fuel

Close

ENGINE EXPLODED VIEW

114- 3.3

68.05

Open

Metering Needle

SUPER AIR CLEANER 202 ASSEMBLY
On-road Type (72412000)
202 Cleaner Body
(72412100)
202 Filter Element (4pcs.)(72412200)

UNF1/4-28

23.5

Needle Valve

3. At the end of each operating session, drain out any fuelthat may remain in the fuel tank. Afterwards,energize
the glow-plug and try to restart the engine, to burn off
any fuel that may remain inside the engine. Repeat thisprocedure until the engine fails to fire. Do this while theengine is still warm.

13.5

FINAL ADJUSTMENT

Final adjustment should be carried out only after therunning-in has been completed.

26
39
The specifications are subject to alteration for improvement without notice.

29.5

50.0

6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan TEL. (06)6702-0225
http://www.os-engines.co.jp
FAX. (06)6704-2722
Copyright 2020 by O.S. Engines Mfg. Co., Ltd. All rights reserved. Printed in JAPAN.

60093700

102000