O.S. engine MAX-50SX Ring, MAX-91FX Ring, MAX-61FX, MAX-40FX, MAX-46FX Owner's Manual
It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-6 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 aircraft, radio control equipment, etc.,
are accessible for checking at the same time.
1
CONTENTS
SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE
FEATURES OF FX SERIES ENGINES,
BEFORE
INSTALLING THE ENGINE
BASIC ENGINE PARTS
NEEDLE-VALVE LOCATION
INSTALLATION OF THE ENGINE
THROTTLE LINKAGE, SILENCER
FUEL TANK LOCATION
GLOWPLUG
FUEL, PROPELLERS
MIXTURE CONTROLS
BEFORE STARTING
RUNNING-IN (Breaking-in)
IDLING ADJUSTMENT CHART
MIXTURE CONTROL VALVE ADJUSTMENT,
REALIGNMENT OF MIXTURE CONTROL VALVE
SUBSEQUENT STARTING PROCEDURE
SUBSEQUENT READJUSTMENT
CARBURETOR CLEANLINESS,
ENGINE CARE AND MAINTENANCE
ENGINE EXPLODED VIEWS &
ENGINE PARTS LISTS
CARBURETOR EXPLODED VIEWS
& PARTS LISTS
GENUINE O.S. PARTS & ACCESSORIES
ENGINE THREE VIEW DRAWINGS
2-6
7
8
8-10
10-11
11-12
12
13
14-15
15
16-17
STARTING
17-18
19-21
22
23
24
25
37-38
26-33
34-36
39-42
2
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.
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
Th ese co ver ev ents which
mig ht inv olve s erio us (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.
3
WARNINGS
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.
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.
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.
A weakened or loose propeller may
disintegrate or be thrown off and, since
propeller tip speeds with powerful
engines may exceed 600 feet(180 metres)
per second, it will be understood that
such a failure could result in serious
injury, (see 'NOTES' section relating to
propeller safety).
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.
4
NOTES
This engine was designed for model
aircraft. 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.
Be sure to use the silencer (muffler)
supplied with the engine. 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.
Install a top-quality propeller of the
diameter and pitch specified for the engine
and aircraft. Locate 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 nut, using the
correct size wrench.
If you remove the glowplug from the engine
and check its condition by connecting the
battery leads to it, do not hold the plug with
bare fingers.Use an appropriate tool or a
folded piece of cloth.
5
NOTES
If you fit a spinner, make sure that it is a
precision made product and that the slots
for the propeller blades do not cut into the
blade roots and weaken them.
Preferably, use an electric starter. The
wearing of safety glasses is also strongly
recommended.
Discard any propeller which has become
split, cracked, nicked or otherwise rendered
uns afe. Never attempt to repair such a
propeller: destroy it. Do not modify a propeller
in any way, unless you are highly experienced
in tuning propell er s for specializ ed
competition work such as pylon-racing.
Take care that the glow plug clip or battery
leads do not come into contact with the
propeller. Also check the linkage to the
throttle arm. A disconnected linkage could
also foul the propeller.
After starting the engine, carry out any
needle-valve readjustments from a safe
position behind the rotating propeller. Stop
the engine before attempting to make other
adjustments to the carburetor.
Always check the tightness of the propeller
nut and retighten it, if necessary, before
restarting the engine, particularly in the
case of four-stroke-cycle engines. If a
safety locknut assembly is provided with
your engine, always use it. This will prevent
the propeller from flying off in the event of a
"backfire", even if it loosens. Also, check
the tightness of all the screws and nuts
before restarting the engine.
6
NOTES
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 propeller.Do not carry loose
objects (such as pencils, screwdrivers, etc.)
in a shirt pocket from where they could fall
through the propeller arc.
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.
For their safety, keep all onlookers
(especially small children) well back (at
least 20 feet or 6 meters) 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.
Keep the propeller pointed away from you
and walk well clear of spectators.
Warning! Immediately after a glowplugignition engine has been run and is still
warm, conditions sometimes exist whereby
it is just possible for the engine to abruptly
restart if the propeller is casually flipped
over compression WITHOUT the glowplug
battery being reconnected. Remember this
if you wish to avoid the risk of a painfully
rapped knuckle!
7
This range of engines is ideally suited to a variety
of R/C aircraft, including trainer, sports, aerobatic
and scale types.
A separate precision-made needle-valve unit is
installed at the rear, where manual adjustment is
safely remote from the rotating propeller.
With the 50SX, 61FX and 91FX, the needle-valve
assembly can be installed either horizontally or
vertically.
FEATURES OF FX SERIES ENGINES
With these engines, the piston will feel tight at the
top of its stroke when the engine is cold. This is
normal. The piston and cylinder are designed to
achieve a perfect running clearance when they
reach their intended running temperature.
Note :
Carefully inser t plug, with
washer, fingertight only, before
final tightening with the correct
size plug wrench.
BEFORE INSTALLING THE ENGINE
Installing the glowplug
Connect the shor t length of fuel tubing (supplied)
securely between the needle-valve outlet and
carburetor inlet as shown in the illustration on the next
page.
In the event of the tubing becoming damaged, it
should be replaced with a suitable length (as
indicated below) of best quality 5mm ODx2mm ID
silicone tubing. Use similar material to connect the
fuel inlet nipple to the fuel tank.
Connecting fuel tubing
Length
40,46FX
54-56mm 61FX
91FX
54-56mm
62mm
Glow plug
Washer
50SX
44-46mm
Length
Silicone Tube, Instruction Manual
Common to accessories
50SX, 40/46FX
61FX
91FX
873 Silencer Assembly
E-4010 Silencer Assembly
E-4020 Silencer Assembly
Needle Valve Extension Cable
Type of engines
Type of engines
8
As delivered from the factory, the MAX-61FX has its
need le-valve a ssembly installed horizontally.
However, if more convenient for a particular
installation, the needle-valve may be reinstalled
vertically behind the cylinder. (See sketch opposite.)
Please note that the needle-valve knob has a center
hole and set-screw for the fitting of a piano-wire
extension so that, when relocated vertically, the
extension enables adjustments to be made without
risk of burning one's fingers on the cylinder head.
NEEDLE-VALVE LOCATION
BASIC ENGINE PARTS
Cylinder head
Carburetor
Silicone Tube
Crankshaft
Propeller nut
Propeller washer
Drive Hub
Crankcase
Needle valve
Cover Plate
Fuel outlet
Fuel inlet
Glowplug
Fuel inlet
Beam Mount
MAX-61FX
Throttle
Lever
Throttle Stop Screw
Using 8mm wrench, remove complete needle-valve
holder assembly including needle, from side of
cover plate.
Remove fuel inlet assembly from upper boss of
cover plate.
Transfer banjo type fuel inlet including washers, to
needle-valve holder and carefully screw complete
assembly into upper boss vacated by fuel inlet
assembly. Tighten very carefully.
The proce
dure for relocating the needle-valve vertically
is as follows:
1.
2.
3.
9
Inlet Holder
Plug Screw
Fuel Inlet
Needle-Valve
Assembly
Needle Extension
Inlet Holder
Fuel Inlet
Needle-Valve
Assembly
45mm
Fuel Inlet
Needle-Valve
Assembly
Plug Screw
Fuel Inlet
Needle-Valve
Assembly
Needle Extension
45mm
61FX
50SX
Use hexagon-head brass inlet holder (61FX) or
plug screw (50SX) to blank off side boss vacated
by needle- valve assembly.
4.
As delivered from the factory, the 91FX has the
needle-valve assembly installed vertically. However, if
more convenient for a par ticular installation, the
needle-valve may be reinstalled horizontally.
The procedure for relocating the needle-valve is as
follows:
Remove the two cover-plate screws which secure
the needle-valve assembly bracket, then carefully
remove the two screws by which the needle-valve
unit is attached to the bracket.
1.
10
Mounting Screw Size
50SX, 40, 46FX
61, 91FX
3mm
4mm
INSTALLATION OF THE ENGINE
Rigid hardwood
(e.g. maple)
At least
15mm(5/8")
At least
15mm(5/8")
O.S. radial motor mount
(Available as an optional extra
part. See parts list)
A typical method of beam
mounting is shown below, left.
Installation in the model
50SX
40, 46FX
61, 91FX
For 50SX, 40/46FX(Code No. 71913100)
For 60FP, 61, 91FX(Code No. 71905200)
Finally, secure the complete assembly to rear cover
plate as before.
3.
Vertical position
(Factory position)
Horizontal position
Cover plate fitting holes
Needle Valve unit
Needle Valve unit Retaining screws
Needle Stay
As self-tapping screws are used for unit
attachment, screw them in carefully so that screw
threads match those of the unit body precisely.
Note:
Rotate the needle-valve unit through 90˚ and reattach it to the bracket in the required position (see
sketch below).
2.
91FX
11
Before connecting the throttle-lever/servo linkage,
make sure that no part of the linkage interferes with
the internal structure of the aircraft or wiring, etc.,
when the throttle is fully open or fully closed.
Set the throttle lever linkage so that the throttle rotor is
(a) fully open when the transmitter throttle stick is fully
advanced and (b) fully closed when the throttle stick
is fully retarded. Adjustment of the throttle rotor opening at the idling position can then be made with the
throttle trim lever on the transmitter. (Select throttlelever and servo-horn hole positions that will avoid excessive pushrod travel causing the throttle to bind at
either end.)
THROTTLE LINKAGE
Note: When adjusting the throttle lever angle,
relative to the rotor,hold the rotor at about half-way
between the open and closed positions while
loosening and tightening the fixing screw, otherwise
the rotor, rotor guide screw,throttle stop screw or
carburettor body may become burred and damaged.
The exhaust outlet of the silencer can be rotated to
any desired position in the following manner:
SILENCER
Hardwood mounting beams
O.S. radial motor
mount
(cast aluminum)
How to fasten the mounting screws.
Make sure that the mounting beams are parallel and
that their top surfaces are in the same plane.
Front view Side view
Top surfaces
are not in the
same plane.
Opposite
beam
Top surfaces
are not in the
same plane.
Re-align the surfaces
as necessary
Engine does not
rest firmly.
CORRECT INCORRECT
Top surfaces are in
the same plane.
Tighten second
nut firmly down
onto first nut.
Tighten this
nut first.
Steel washer
3-4mm
steel screw
Spring
washer or
lock washer
Hardwood such
as cherry or maple.
Spring
washer
3.5mm steel
Allen screw
3-4mm steel nuts
Use mounting screws of a diameter
(between 3mm and 4mm) appropriate
to engine size (see table left).
12
Suggested fuel tank capacities are listed opposite.
These will allow 12-13 minute flights.
Locate the fuel tank so that the top of the tank is 510mm (1/4-3/8") above the level of the needle-valve.
Be sure to use a pressurized fuel system by
connecting the muffler pressure nipple to the ventpipe of the fuel tank.
Suggested Fuel Tank Capacities
50SX
40,46FX
approx 300cc
approx 350cc
approx 450cc
61FX
91FX
FUEL TANK LOCATION
Attention to tank height
•
Fuel level
10mm
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. Keep your hands and face away from
exhaust gas or you will suffer a burn.
Reminder!
Loosen the locknut and assembly screw.
Set the exhaust outlet at the required position by
rotating the rear part of the silencer.
Re-tighten the assembly screw, followed by the
locknut.
1)
2)
3)
NOTE :
The standard expansion-chamber type silencer is
quite effective, but reduces power to some degree.
Assembly screw
Cone baffle
Turn to requlred position
Exhaust outlet
Locknut
Exhaust pressure nipple
E-4010 Silencer
13
The role of the glowplug
With a glowplug engine, ignition is initiated by the
application of a 1.5-volt power source. When the battery
is disconnected, the heat retained within the combustion
chamber remains sufficient to keep the plug filament
glowing, thereby continuing to keep the engine running.
Ignition timing is 'automatic' : under reduced load,
allowing higher rpm, the plug becomes hotter and,
appropriat ely, fir es the fuel/a ir charg e earlie r;
conversely, at reduced rpm, the plug become cooler and
ignition is retarded.
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of
nitromethane unless more is essential for racing
events.
Do not run the engine too lean and do not leave the
battery connected while adjusting the needle.
However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
When to replace the glowplug
Filament surface has roughened and turned white.
Filament coil has become distorted.
Foreign matter has adhered to filament or plug
body has corroded.
Engine tends to cut out when idling.
Starting qualities deteriorate.
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items.
Since the glowplug and fuel combination used may
have a marked effect on performance and reliability, it
would be worthwhile to experiment with different plug
types.
Recommended O.S. plugs are Nos. 8, A5 and A3.
Carefully install plug finger-tight, before final tightening with the correct size plug wrench.
GLOWPLUG
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