O.S. Engines 37SZ-H User Manual

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