O.S. Engines GT60 User Manual

Two stroke gasoline engine for airplanes

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

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.

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.

NOTES

These cover the many other possibilities, generally
less obvious sources of danger, but which, under
certain circumstances, may also cause damage or
injury.

WARNINGS

Never touch, or allow any object to come
into contact with the rotating propeller and
do not crouch over the engine when it is
running.

Gasoline is poisonous. Do not allow it
come into contact with the eyes or mouth.
Always store it in a clearly marked
container in a cool and dark place and out
of the reach of children. There is a
possibility that it may damage your health.

Gasoline is highly flammable. Keep it away
from an open flame, excessive heat,
sources of sparks, or anything else which
might cause it to ignite. Do not smoke or
allow anyone else to smoke near to it.

ABOUT THE ENGINE

This engine is designed for experienced fliers.
Beginners and newcomers should not use this engine.

The engine unit, silencer and carburetor are
specially designed.

The normal rotation direction of the engine is
counterclockwise facing to the propeller.

It offers broad power characteristics suitable for
sport flight as well as acro flight.

The specially designed ignition module “IG-02” is
equipped with a micro computer and designed not to
operate below 120 rpm.

The new E-6020 silencer develops very efficient silencing.

The engine can be easily choked for starting by
connecting a choke rod (not supplied) to the
carburetor choke lever.

STANDARD ACCESSORIES

Spark Plug CM-6

Ignition module
Assembly (IG-02)

Propeller Washer

Cap Screw M5x45

E-6020 Silencer

Exhaust Gasket
Cap Screw M5x50
M5 Washer

#38608 GT60 w/o muffler does not include the above
muffler set.

Carry out the mixing of the gasoline and
oil outdoors or in a well ventilated place
away from any source of fire to prevent the
possibility of a fire.

Refill the fuel tank only after the engine is
well cooled down, or there is a danger of
fire.

Model engines generates 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 results in a serious
burn.

Observe the laws and regulations in each
country and district concerning the usage,
transportation and storage of gasoline. Ask
details at fire station in each district.

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.

Do not operate the engine nor model alone, or
there is a possibility of injury.

NOTES

Any propeller requires utmost attention to handle.
Be sure to follow the instruction manual supplied with
a propeller.

This engine was designed for model aircraft.
Do not attempt to use it for any other purpose.

Start the engine only after installing it in the model.
Do not start the engine before installing it in the
model, or there is a possibility of injury.

Be sure to use an effective silencer (muffler).
Frequent exposure to an open exhaust may
eventually impair your hearing. Such noise is also
likely to cause annoyance to others over a wide area.

Mount the engine in your model securely, following
the manufacturers’ recommendations.

For their safety, keep all onlookers (especially small
children) well back (at least 10 meters) when
preparing your model for flight.

When checking a spark plug with the power source
on, do not hold the plug, plug cap, high tension cord ,
or you will get a shock.

Install a top-quality propeller of the diameter and
pitch specified for the engine and aircraft.

ENGINE PARTS NAME

Spark Plug

Cylinder Block

Front Housing

Drive Spacer

RPM Sensor

Pilot Shaft

Propeller Washer

High Tension Cord

INSTALLATION

Use a strong enough material for the mounting face
of the model, such as birch ply firewall of more than
8mm thick.

Make sure the mounting face of the model is flat. If it is
uneven, work on it to be flat. (When shims are added
to change the thrust angle, work on it to be flat.)

Engine mounting face has been high-precision
machined flat. Make sure mounting face of the
model is also flat.

E-6020 Silencer

Carburetor Complete
HDA-313

Sensor Leads

Rear Housing

Battery Leads

Sensor Leads

Discard any propeller which has become split,
cracked, nicked or otherwise rendered unsafe.
Never attempt to repair such a propeller: destroy it.
Do not modify a propeller in any way.

Install the propeller on the shaft so that the curved
face of the blades faces forward – i.e. in the direction
of flight. Firmly tighten the propeller washer and
propeller installing screws using the correct size
wrench. Always check the tightness of propeller
installing screws and retighten them, if necessary,
before starting the engine. Also, check the tightness
of all the screws and nuts before restarting the
engine.

Always check the throttle linkage.If it is disconnected,
throttle action becomes uncontrollable, which may
result in a serious accident.

Take care that loose clothing (ties, shirt sleeves,
scarves, etc.) do not come into contact with the
propeller. Do not carry loose objects (such as
pencils, screwdrivers, etc.) in a shirt pocket from
where they could fall through the propeller arc.

Use an electric starter for this engine. The wearing of
safety glasses is also strongly recommended.
If you try hand starting, be sure to use a chicken stick
or heavy glove. Never attempt to start the engine
with a bare hand.

Be sure to carry out adjustments of the high speed
needle and slow speed needle after stopping the
engine.

Do not start your engine in an area containing loose
gravel or sand. The propeller may throw such
material in your face and eyes and cause injury.

If you have to carry the model to the take-off point
with the engine running, be especially cautious.
Keep the propeller pointed away from you and walk
well clear of spectators.

Switch off the ignition module to stop the engine or
fully close the throttle valve via the transmitter to
shut off the fuel supply. Otherwise there is a
possibility of injury.

Immediately after the engine is stopped, the engine
may start with a crank even when the igniter switch
is off. Do not crank the engine, or there is a
possibility of injury.

Be sure to install an externally operable switch for
the ignition system battery to stop the engine if it is
started unintentionally with the radio transmitter
turned off or there is the possibility of injury.

Connect the throttle linkage so that the engine can
be stopped via radio operation.

Use 5mm steel hex socket head bolts to install the
engine. (Do not use brass, soft steel nor aluminum
screws, because they are not strong enough.) Also,
use the Nord Lock Washers (optional extra) and
other anti-loosening washers or apply locking agent.

Be sure that there is sufficient air intake and outlet
area on the model for engine cooling to avoid
overheating. (Pay careful attention to the cooling
since a gasoline engine generates more heat than a
glow engine.)

Secure at least a 30mm dia. area around the air
intake of the carburetor so that the air intake will not
be restricted. (Cut out the firewall big enough if
necessary.)

FUEL TANK & LINES

Use a tank designed for gasoline. (Tanks designed
for glow fuel use a rubber cap which is deteriorated
by gasoline.)

A 600cc tank will provide 12~13 minutes flight.
(With full throttle, it will provide 7~8 minutes flight.)

Install a commercially available gasoline fuel filter
between fuel tank and carburetor. (Clean the filter
from time to time.)

For plumbing use TYGON F-4040 (Yellow color) or
strong nitrile rubber of more than 3mm ID and 6mm
OD. Replace tubing periodically as it becomes
hardened. (Replace tubing inside the fuel tank every
six months.)

Use fuel line keepers of stainless wire, etc. at the
end of the tubing to prevent at from coming off.

This engine does not require a muffler pressurized
fuel system but be sure to provide an air vent.

Be sure to install an in-line fuel filter between the
tank and carburetor to prevent foreign matter in the
tank from entering the carburetor. Clean the filter
periodically.

Be sure to equip
air vent pipe.

Be sure to use fuel line keepers of
stainless wire, etc. to prevent tubing
from coming off.

Be sure to replace tubing
inside periodically.

To carburetor
fuel inlet

tubing for
re-fuelling

Be sure to use a gasoline
resistant fuel tank cap.

CARBURETOR PARTS NAME

Fuel Inlet

Throttle Valve Lever
Retaining Screw

Throttle Valve

Throttle Valve Lever

Throttle Valve
Lever

Close

Throttle

Slow Speed Needle

Choke Valve
Lever

Choke Valve
Lever

Open

Open
(OFF)

High Speed
Needle

Choke Valve

Choke Valve Lever
Retaining Screw

Close

Choke

(ON)

CARBURETOR LINKAGE

NOTE
When changing the throttle valve lever and choke
valve lever direction, loosen and tighten each
retaining screw placing each lever at mid position.
(If the throttle valve lever retaining screw is
loosened or tightened with the throttle valve fully
opened or closed, excessive force will be applied,
which will results in breaking the lever.)

Before connecting the throttle linkage, make sure
that the throttle valve lever does not interfere with
the bulkhead or mount of the model when it is fully
closed and opened.

In order to obtain suitable idling, connect the throttle
linkage so that the throttle valve lever may be
located at 2 to 3 degrees opened position from fully
closed position when the throttle stick on the
transmitter is fully pulled down, and the throttle valve
may be fully closed when the throttle stick as well as
the rim lever on the transmitter are fully pulled down
or engine cut-off mixing is operated.

Connect the linkage so that the throttle valve is fully
opened when the throttle stick on the transmitter is
fully advanced. (Adjust the movement so that the
pushrod does not bind when the throttle valve is fully
closed and fully opened.)

Connect the linkage so that the servo arm and
pushrod, and throttle valve lever make a right angle
when the throttle stick on the transmitter is placed at
mid position to avoid differential action.

Choke valve rod Linkage

(OFF)

Close

Choke

(ON)

Open

Connect the linkage
as illustrated.

NOTE
Linkage parts are
not supplied.

IGNITION MODULE

Major specifications

Consumption current is 600mA/6,000rpm. User a
power source of more than 1000mAh capacity.

The ignition module is set not to operate below
120rpm for safety.

The voltage of power source is 4.8~7.6V (rated).
(Ni-Cd, Ni-MH 4~6 cells, Li-Po, Li-Fe 2 cells)

Installation

Install the ignition module taking sufficient
anti-vibration measures.

Install the ignition module at least 100mm away
from the engine and in a place where there is airflow
so that engine exhaust heat and radiation heat do
not affect it's operation.

Do not share the power source with receiver and
use a separate power source.

Equip an ON/OFF switch between the ignition
module and its power source and install it in a place
where can be operated from outside the model.

Install the ignition module and its power source as
far as possible away from the servos and receiver
power source.

Connect the sensor leads of the igniter module
(while, red, black three parallel wires) to the sensor
leads from the engine.

Connect the battery leads of the igniter module (red,
black two parallel wires) to the power source.

Make sure the jackets of high tension cord does not
touch the engine and cowl to avoid accidental short
circuit.

Install he plug cap on the plug securely.

Precautions

Do not disassemble the ignition module and plug
cap. (The ignition module is irreparable. Replace it
when necessary.)

Be careful not to mount the ignition module so that it
can be hit by water, gasoline or exhaust.

Avoid using the engine when the external
temperature is over 40 C.

Do not move the rpm sensor as it is placed at it's
optimum position, otherwise the engine will not run
properly.

Do not pull on the high tension cord to remove the
plug cap, or the wire will break. Be sure to hold the
plug cap to remove it. Be careful not to damage
your fingers while removing it.

Do not connect nor disconnect the rpm sensor with
the ignition module on, or there is a possibility it will
fire and the engine start.

Check the ignition module for spark when installing
the plug cap on the plug and be careful about
getting a shock. Make sure there is no flammable
material or gasoline vapors near by that could
ignite.

Do not turn the propeller with the ignition module
on, or there is a possibility the engine will start.

PROPELLER

Use a wooden or a carbon fiber propeller.
Do not use a nylon propeller.

The choice of propeller depends on the design and
weight of the aircraft and on the type of flying in which
you will be engaged. Determine the best size and type
after practical experimentation. As s starting point,
refer to the props listed in the table shown below.
Slightly larger, or even slightly smaller props than those
shown in the table may be used, but remember that
propeller noise will increase if blade tip velocity is
raised due to high rpm or if a larger diameter/lower
pitch prop is used. Be well aware propeller rotating arc
is very large due to a large propeller used with this
engine. Carry out the needle adjustments only after
stopping the engine. Do not allow your face or hands to
come close to the rotating prop.

Type

Running-in

Acro/Scale

23x8
22x10-12 23x8-10

24x8-10

Size (DxP)

Warning:
Make sure that the propeller is well balanced.
An unbalanced propeller and/or spinner can cause
serious vibration which may weaken parts of the
airframe or affect the safety of the radio-control
system. Do not use any propeller which has
become split, cracked or nicked even very slightly,
or received strong impact even if no apparent
damage is visible.

PROPELLER & SPINNER ATTACHMENT

If the supplied retaining screws are too long due to a
thinner prop hub or too short due to a thicker prop
hub (cannot be screwed into the drive hub by more
than 10mm), Use suitable length strong steel hex
socket head cap screws.

Install the propeller before the first flight of the day
and remove it after the day’s flight.

Make a habit of always checking the tightness of
propeller retaining screws making sure they are free
of, damage or rust before starting the engine.
Replace the propeller periodically (every 50 flights)
even if it looks as ifs nothing is wrong.

Since the GT60 is intended to be started with an
electric starter, the addition of a spinner assembly for
centering the starter sleeve is desirable. Special
propeller locknut sets are available for use with
spinners. Use a good quality well balanced spinner,
enclosing the propeller boss. Make sure that it is of
precision-made and sturdy construction so that the
spinner shell cannot loosen when the starter is used.
Make sure the spinner notches do not interfere the
propeller. If they do, cut the notches to clear.

MIXING OF OIL

Use regular gasoline. (No need to use high octane
gasoline.)

Alcohol based glow fuel cannot be used in this
engine. Not only will the engine not work properly
but the internal carburetor plastic parts will be
damaged.

Use high quality commercially available 2 stroke
engine oil.

Follow the oil manufacturer’s recommendations
concerning the mixture ratio of gasoline and oil. If
there is no recommendation, mix with a 30:1 ratio.
We have checked and approved the following oil
mixture ratio. KLOTZ ModelLube (50:1), COSMO
Cosmo Terra 2 cycle (50:1), RED LINE Two-Stroke
Racing Oil (40:1). (This does not mean we
guarantee the quality of these oils.)
Follow the instructions in the running-in section
concerning the mixture for running-in.

With a gasoline engine, passages in the carburetor
are narrower than that of a glow engine, and
therefore very sensitive against foreign matter such
as dust. It is suggested to use optional accessory
Super Filter L (Code No. 72403050) when filling a
tank in the model from a container used for
transportation or storing.

RUNNING-IN / STARTING

Use a fuel with increased oil content and set the
needle a little on the rich side. Too rich a needle
setting may cause misfiring or erratic running due to
fouling of the plug.

Use a 25:1 fuel/oil mixture if the particular brand of
oil states 50:1 mix. Use a 20:1 fuel/oil mixture if the
particular brand of oil states 30:1 mix. Set only the
high speed needle 200 below maximum rpm. The
low speed needle need not be richened.

No need to carry out running-in on a bench nor with
the model fixed. Just fly the model with the above
mentioned fuel and needle setting.

A total of 10 flights (5~6 litters fuel) are required.
Avoid prolonged full throttle running at initial stage,
and gradually extend the full throttle running time.

WARNING:
When ground running the engine, avoid dusty or
sandy locations. If dust or grit is drawn into the
engine, this can have a ruinous effect, drastically
shortening engine life in a matter of minutes.