O.S. Engine GT15HZ600 Owner's Instruction Manual

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ABOUT THE ENGINE

STANDARD ACCESSORIES

Spark Plug CM-6

Ignition Module

Assembly (IG-05)

PowerBoost Pipe GT15HZ

(Included only in code #38173 GT15HZ600

W/PowerBoost Pipe)

Two stroke gasoline engine for helicopter

It is of vital importance, before attempting to operate your 

engine, to read the general 'SAFETY INSTRUCTIONS 

AND WARNINGS' in the following section and to strictly 

adhere to the advice contained therein.

Also, please study the entire contents of this 

instruction manual, so as to familiarize yourself with 

the controls and other features of the engine.

SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE

The advice which follows is grouped under two 

headings according to the degree of damage or 

danger which might arise through misuse or neglect.

WARNINGS

NOTES

These cover events which might involve serious 

(in extreme circumstances, even fatal) injury.

These cover the many other possibilities, generally less 

obvious sources of danger, but which, under certain 

circumstances, may also cause damage or injury.

Remember that your engine is not a " toy ", but a 

highly efficient internal-combustion machine whose 

power is capable of harming you, or others, if it is 

misused or abused. As owner, you alone are 

responsible for the safe operation of your engine, so 

act with discretion and care at all times. If at some 

future date, your O.S. engine is acquired by another 

person, we would respectfully request that these 

instructions are also passed on to its new owner.

Never touch, or allow any object to come 

into contact with, the rotating parts.

Gasoline is poisonous. Do not allow it to 

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.

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 for 

details at the 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 or model alone, or 

there is a possibility of injury.

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.

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.

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.

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 ignition 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.

This engine was designed for model helicopters. 

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.

NOTES

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.

Always check the throttle linkage.If it is disconnected, 

throttle action becomes uncontrollable, which may 

result in a serious accident.

Use an electric starter for this engine. The wearing of 

safety glasses is also strongly recommended.

Press the rotor head down securely.

Be sure to carry out adjustments of the high speed 

needle and slow speed needle after stopping the 

engine.

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.

WARNINGS

ENGINE PARTS NAME

Battery Leads

Sensor Leads

High Tension Cord

Spark Plug

Carburetor

Complete 61HA

Sensor

Leads

RPM

Sensor

Drive Hub

Crankshaft

Heatsink Head

Propeller Nut

Ignition module (IG-05)

Cover

Plate

INSTALLATION OF THE ENGINE

CARBURETOR PARTS NAME

LINKAGE TO THE CARBURETOR 

Fig.1

IGNITION MODULE

Major specifications

Consumption current is 750mA/14,000rpm/6.0V. 

User a power source of more than 1500mAh 

capacity.

The voltage of power source is 4.8~8.4V (rated). 

(Ni-Cd, Ni-MH 4~6 cells, Li-Po, Li-Fe 2 cells)

Installation

Install the ignition module taking sufficient 

anti-vibration measures.

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.

Install the module to the place where good ventilation is 

secured because it becomes hot when the engine runs.

Hold the high tension cord to the frame to prevent 

from breaking due to vibration.

Throttle Lever

This engine is designed to be expressly run by gasoline fuel.

Carburetor is set at the factory when the engine leaves the factory.

First run the engine with this factory settings. Refer to the INITIAL OPENING 

OF THE NEEDLES described later concerning the factory settings.

Use the Powerboost Pipe GT15HZ (code no. 72148000) with GT15HZ600.  

Using a silencer developed for glow engines may cause overheating.  

Any damages caused by a use of such silencer are not covered under 

warranty.

Be aware of long flight time due to low fuel consumption.

3 Be sure to use a power source of more than 1500mAh capacity for the 

receiver when more than 15 minutes of flight is expected.  Also, it is suggested 

to check the remaining level frequently and charge the batteries if necessary.

Do not run the engine at high rpm abruptly after 

starting the engine, or you will be injured by rotating 

rotor.

Be sure to use an electric starter and wear safety 

goggles and gloves when starting the engine, or you 

will be injured.

Install the cooling fan and clutch on the engine, then 

install the engine in the model referring to the 

instruction manual supplied with the model. 

At this time some small modifications are required 

so that the carburetor parts may not interfere with 

the cooling duct. 

Select either F lever or J lever of 

the Throttle Valve Lever supplied 

according to the servo used.

Select a hole so that both servo 

horn and Throttle Valve Lever make 

right angle against the linkage rod.  

Cut off the levers not in use with 

nippers.

Cut off the levers

not in use.

This is a component for igniting a spark plug. Install 

the plug cap on the plug by using force to push it to 

the root.  Then, install the module in the model.

Do not grip the engine mounting beams with a vise, or 

the crankcase will be distorted which will result in 

engine breaking. 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.

NOTES ON INSTALLING COOLING FAN AND CLUTCH

Since a gasoline engine uses a spark ignition system it is possible that radio 

frequency noise from the ignition module can interfere with the receivers 

operation if a 72MHz or 40MHz radio is used. Therefore it is recommended that 

a 2.4GHz radio system be used, which is not effected by radio frequency noise.

It is recommended to use 2.4GHz transmitter/receiver. 

600929900000

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

Mix commercially available 2 stroke engine oil with a 25:1 ratio. Pre-mixed 

gasoline is also usable but do not use such as pre-mixed gasoline which 

requires the needle settings far away from the factory settings, otherwise 

needle settings would be very difficult.

GT15HZ600

ID.２mm×OD.4mm×150mm Length

Pump Unit PD-08 1pc.

Fluororubber Tube 1pc.

Crankcase

Heatsink

Locking piston by inserting a tool from the 

plug hole or exhaust port while installing 

the cooling fan and clutch may damage 

the engine.

When removing and installing the cover plate, be 

sure to do it with the piston at TDC. Otherwise it 

is possible the piston skirt will interfere with the 

cover plate and become damaged.

71530510 and 71530520 cannot be used with the 

GT15HZ600.  If they are used, piston skirt will become 

broken or damaged.

We strongly recommend to use Crankshaft Clamp 

91/105/GT15 (Code No.71530530) available as an 

optional tool. 

The O.S. Crankshaft Clamp is a must-have for 

installing the cooling fan!!

Regulator

Needle Valve

Mixture Control Valve

Throttle Lever

Fuel Inlet

NEVER disassemble the fuel pump or pressure 

regulator. Their original performance may not be 

restored after reassembly.

DO NOT allow foreign matter to enter the fuel 

system. Dirt inside the pump or regulator, no matter 

how small, may obstruct the flow of fuel and prevent 

these components from working properly.

CARE OF FUEL PUMP & REGULATOR

DO NOT obstruct the small rectangular hole at the 

bottom of the regulator, or the regulator will not 

function correctly.

NEVER insert anything into the inlet or outlet nipples 

in an attempt to clear a suspected obstruction.

ALWAYS use fuel filters. Keep the fuel tank 

scrupulously clean and filter all fuel as it enters the 

tank (e.g.via an O.S.'Super-Filter' Code No.72403050) 

and use a good quality in-line filter between the tank 

and pump. Remember to inspect filter screens at 

regular intervals and rinse clean as necessary.

Rectangular

hole

NEVER use kerosene, thinner or any organic solvent 

for cleansing the pump. Rubber parts will be ruined 

by these materials. Use only alcohol (methanol) or 

gasoline.

The Needle-Valve

For adjusting the mixture strength when the throttle is 

fully open Needle-valve adjustment effect the mixture 

strength at round mid speed.

The Mixture Control Valve

For adjusting the mixture strength at part-throttle and 

idle speed, to obtain steady idling and smooth 

acceleration to mid speed.

Two adjustable controls are provided on this 

carburetor.

Therefore, it is required to adjust also the needle-valve 

when the mixture control valve is adjusted. Mixture 

control valve is pre-set at nearly best position when the 

engine leaves the factory.  Therefore, it is not necessary 

to adjust the mixture control valve until running-in is 

completed.

INITIAL OPENING OF THE NEEDLES

This carburetor is equipped with the following two 

needles.

The Needle-Valve

The default setting is made at the factory.  This is to 

adjust the fuel mixture from idling to hovering.

The Mixture Control Valve

Open it 2.5-3.0 turns from the fully closed position. 

This is to adjust from hovering to the flight up in the 

air.

The initial opening is just a basic position and not 

necessarily the optimum position.

Carry out adjustments according to the procedures 

described in the NEEDLE ADJUSTMENTS section.

GT15HZ600 How to correctly fit the plug cap to the

spark plug

The GT15HZ600 gasoline engine is equipped with a 

spark plug, and safe flight of the helicopter requires a 

firm connection of the plug cap to the spark plug.  See 

the following instructions for details.

Cylinder head with spark plug

(Pic. 1)

Make sure that the spark plug is 

tight in the head. Apply silicon 

grease to the plug top or inside 

of the plug cap for easy 

connection. (Pic. 2)

(The shown cylinder head is a 

cutaway.)

Correct connection (Pic. 3)

The ‘tight fit’ plug cap is 

designed not to detach from the 

spark plug easily.  Press the plug 

cap firmly until it covers the 

hexagon plug base with a ‘click’.  

The fully connected plug cap in 

the cylinder head doesn’t show 

the stamped “O.S.” logo on its 

side. (Pic. 4)

(Pic. 1)

(Pic. 2)

(Pic. 3)

(Pic. 4)

F

J

F

J

Fig.2

Nylon Nut M3 2pcs.

Pan Head Screw (N.+M3x18) 2pcs.

Plug Cap

This is a 2-stroke 15cc gasoline engine GT15HZ600 

expressly designed for 600 size (50 glow engine class) 

R/C helicopters. Its mount size is the same as GT15HZ, 

which is for 700 size (90 glow engine class) helicopters, 

but the crankshaft diameter of the threaded part is the 

same as standard 50 class glow engine.  Therefore you 

can fit a fan pulley and a clutch of 600 size helicopter 

directly to the crankshaft without modifications.The new 

61HA carburetor achieves linear power transition with a 

combination of pump unit PD-08. #72520000 

conversion kit enables a direct fit to ALIGN T-REX 600N 

helicopter.  The conversion kit consists of Main frames, 

a bottom frame, a pinion gear, a set of engine mount, 

ball bearings, and collars.

5) Use the exclusive silencer

The cooling fan cover for T-REX 700 DFC (ALIGN 

code no. H7NB011XXW) and the optional metal 

engine fan (ALIGN code no. HN6060) for T-REX 

600N are necessary to fit GT15HZ600 to ALIGN 

T-REX 600N helicopter.

Mount the PD-08 Pump Unit on the distant location 

from the engine, where it can get good ventilation but 

within the reach of the accessory tube.  Mounting the 

Pump Unit close to the engine cover plate may cause 

malfunction of the Pump Unit due to high temperature.  

Connect the nipple in the back of the Pump Unit to the 

engine cover plate nipple with the Fluoro-rubber Tube 

(included).  The tube length should be around 10 cm.  

Put a piece of tube around the end of the fuel tube as 

shown in Fig 1 to prevent the tube from coming off.

MOUNTING THE PUMP UNIT

Fuel Tube (included)

Put a piece of tube around the Fuel Tube

to prevent the fuel tube from coming off.

Carry out the linkage making sure of the moving 

direction of the throttle valve.  The moving angle of the 

throttle valve from fully closed position to fully opened 

position is 85 degrees.  Connect the throttle linkage so 

that the engine can be completely stopped via radio 

operation.  The throttle opening when starting should 

be approx. 30 % of the total movement.  After starting 

the engine, you can set the idling position lower as the 

engine is warming up.  We recommend you to set a 

specified starting mode in a vacant idle-up channel for 

example idle-up 3, so that you can use the mode until 

the engine warms up.

F

J

J

F

28

34

27

33

Halfway Connection 1 (Pic. 5)

A spark between the plug cap 

and the plug generates radio 

‘noise’, which may cause errors in 

receivers, gyros, governors and 

servos.  The plug cap could also 

detach during flight. (The shown 

cylinder head is a cutaway.)

(Pic. 5)