O.S. engine MAX FXi 46 Setup guide

© Copyright 2003 HCAZ3085
MAX FXi 46
OWNER’S INSTRUCTION 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.

SAFETY INSTRUCTIONS AND WARNINGS
ABOUT YOUR O.S. ENGINE ................................3
FEATURES OF FXi SERIES ENGINE ..................7
BEFORE INSTALLING THE ENGINE....................7
BASIC ENGINE PARTS ........................................8
INSTALLATION OF THE ENGINE ........................8
THROTTLE LINKAGE............................................8
MUFFLER..............................................................9
FUEL TANK LOCATION ........................................9
GLOW PLUG ......................................................10
FUEL....................................................................11
PROPELLERS ....................................................12
MIXTURE CONTROLS........................................12
BEFORE STARTING............................................13
STARTING ..........................................................14
RUNNING-IN (Breaking-in)..................................15
NEEDLE VALVE ADJUSTMENT DIAGRAM........17
MIXTURE CONTROL VALVE ADJUSTMENT ....19
REALIGNMENT OF MIXTURE CONTROLVALVE ..19
SUBSEQUENT STARTING PROCEDURE..........20
SUBSEQUENT READJUSTMENT......................20
CARBURETOR CLEANLINESS..........................21
ENGINE CARE & MAINTENANCE ....................22
O. S. ENGINES LIMITED WARRANTY ..............22
ENGINE EXPLODED VIEW ................................24
ENGINE PARTS LIST..........................................25
CARBURETOR EXPLODED VIEW ....................26
CARBURETOR PARTS LIST ..............................26
CONTENTS
2

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.
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.
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!
These cover events which might involve
serious (in extreme circumstances, even
fatal) injury.
SAFETY INSTRUCTIONS AND
WARNINGS ABOUTYOUR O.S. ENGINE
3

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 muffler supplied with
the engine. Frequent exposure to an
open exhaust may eventually impair
• 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.
• 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.
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.
• A weakened or loose propeller may
disintegrate or be thrown off and, since
propeller tip speeds with powerful
engines
may exceed 600 feet (180 meters)
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 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 fuel.
4

• 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 unsafe. Never
attempt to repair such a propeller,
destroy it. Do not modify a propeller in
any way, unless you are highly
experienced in tuning propellers for
specialized 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.
your hearing.Such noise is also likely to
cause annoyance to others over a
wide area.
• If you remove the glow plug 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.
• 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 face forward–i.e.in the direction of
flight. Firmly tighten the propeller nut,
using the correct size wrench.
• Always check the tightness of the
propeller nut and retighten it, if
necessary, before restarting the engine,
particularly in the case of four-stroke
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.
5

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 glow plug
ignition 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 glow plug battery being
reconnected. Remember this if you
wish to avoid the risk of a painfully
rapped knuckle!
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.
• 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.
6

This range of engines is ideally suited to a
variety of R/C aircraft, including trainer,
sports, acrobatic 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.
Common Accessories
No. 8 Glow Plug, Silicone Tube, Instruction
Manual.
Note: 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.
Installing the Glow Plug
Carefully insert plug, with washer, finger
tight only, before final tightening with the
correct size plug wrench.
Connecting the Fuel Tubing
Connect the short 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 OD x 2mm ID silicone tubing.
Use similar material to connect the fuel inlet
nipple to the fuel tank.
BEFORE INSTALLING THE ENGINE
FEATURES OF FXi SERIES ENGINE
7

Installation in the Model
Make sure that the mounting beams are
parallel and that their top surfaces are in the
same plane.
• 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 LINKAGE
INSTALLATION OF THE ENGINEBASIC ENGINE PARTS
8

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 throttle-lever and
servo-horn hole positions that will
avoid excessive pushrod travel causing
the throttle to bind at either end.)
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 carburetor body may become
burred and damaged.
The exhaust outlet of the silencer can be
rotated to any desired position in the
following manner:
1) Loosen the locknut and assembly screw.
2) Set the exhaust outlet at the required
position by rotating the rear part of
the silencer.
3) Re-tighten the assembly screw,
followed by the locknut.
Note: The standard expansion-chamber
type silencer is quite effective, but
reduces power to some degree.
Reminder: 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.
Suggested fuel tank capacities are listed
opposite.These will allow 12-13 minute flights.
Locate the fuel tank so that the top of the
FUEL TANK LOCATION
MUFFLER
9

tank is 5-10mm (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 vent pipe of the fuel tank.
Since the glow plug 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.
The Role of the Glow Plug
With a glow plug 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, appropriately,
fires the fuel/air charge earlier; conversely, at
reduced RPM, the plug becomes cooler and
ignition is retarded.
Glow Plug Life
Particularly in the case of very high
performance engines, glow plugs must be
regarded as expendable. However, plug life
can be extended and engine performance
maintained by careful use, i.e.:
• Install a plug suitable for the engine.
• Use fuel containing a moderate
percentage of nitro methane 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.
GLOW PLUG
10

When to Replace the Glow Plug
Apart from when actually burned out, a plug
may need to be replaced because it no
longer delivers its best performance, such
as when:
• 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.
Select, by practical tests, the most suitable
fuel from among the best quality fuels
available in your country for model use. For
the best performance, a fuel containing 5%
to 20% nitro methane 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 deteriorate and may
adversely affect running qualities.
Once a satisfactory fuel has been selected
and used for a while, it may be unwise to
needlessly change the brand or type.In any
engine, a change of fuel may cause carbon
deposits in the combustion chamber or on
the piston head to become detached and
lodged elsewhere, with the risk of this
causing unreliable operation for a while. If,
however, the adoption of a different fuel is
unavoidable, check the engine for the first
few flights on the new fuel, by temporarily
reverting to the running-in procedure.
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.
FUEL
11

Reminder! 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.
The suggested propeller size is listed on
page 13.The suitability of the prop depends
on the size and weight of the model and
type of flying. Determine the best size and
type after the engine has been run in.
Check the balance of the propeller before
fitting it to the engine. Unbalanced
propellers cause vibration and loss of
power. Wooden propellers are to be
preferred. Some nylon propellers are not
strong enough to withstand the high power
output of these engines and a thrown blade
can be very dangerous.
Reminder! 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.
Two mixture controls are provided on
these engines.
• The Needle Valve (at rear of engine)
When set to produce maximum power at full
throttle, this establishes the basic fuel/air
mixture strength.The correct mixture is then
maintained by the carburetor's built-in
automatic mixture control system to cover
the engine's requirements at reduced
throttle settings.
• The Mixture ControlValve (carburetor)
This meters fuel flow at part-throttle and
idling speeds to ensure reliable operation
as the throttle is opened and closed. The
Mixture Control Valve is factory set for the
MIXTURE CONTROLS
PROPELLERS
12

approximate best result. First run the
engine as received and readjust the Mixture
Control Screw only if necessary.
Tools, Accessories, etc.
The following items are necessary for
operating the engine.
1–Fuel
Model glow plug engine fuel of good quality,
preferably containing a small percentage of
nitro methane.
2–Glow Plug
O.S. No. 8 glow plug is fitted to the engine.
3–Propeller
Suggested sizes are 9x7, 9x8, 10x5, 10x6,
10x7, 11x5, 11x6.
4–Glow Plug Battery
The power source for heating the glow plug
may be either a large heavy-duty 1.5-volt
dry cell, or preferably, a 2-volt rechargeable
lead-acid cell.
Warning (Very hot): Never touch the
nichrome wire while the battery is
connected.
5–Battery Leads
These are used to conduct current from the
battery to the glow plug. Basically, two
leads, with clips, are required, but, for
greater convenience, twin leads with
special glow plug connectors are
commercially available.
6–Fuel Tank
For installation in the model, a 300cc
(10.6oz.) for 46 FXi is suggested.
7–Fuel Bottle or Pump
For filling the fuel tank, a simple,
polyethylene "squeeze" bottle, with a
suitable spout is all that is required.
Alternatively, one of the purpose-made
manual or electric fuel pumps may be used
BEFORE STARTING
13

to transfer fuel directly from your fuel
container to the fuel tank.
8–Electric Starter and Starter Battery
An electric starter is recommended for
starting.
9–Fuel Can Filter
Fit a filter to the outlet tube of your refueling
container to prevent entry of foreign matter
into the fuel tank.
10–Silicone Tubing
This is required for the connection between
the fuel tank and engine.
11–Plug Wrench
Used for tightening glow plugs. The O.S.
long plug wrench is available as an optional
accessory.
1. Install appropriate propeller and tighten
securely.
2. To facilitate electric starting, install an
O.S.solid aluminum alloy spinner-nut for
centering the rubber drive insert of the
starter. Alternatively, a good quality
spinner, enclosing the propeller boss,
may be used, but make sure that it is of
precision-made and sturdy construction
so that the spinner shell cannot loosen
when the starter is used. Close the
throttle.
3. Fill the fuel tank. Do not allow fuel to
overflow into the silencer, otherwise the
engine may become flooded and
difficult to start.
4. Check that the needle valve is closed.
(Do
not overtighten) Now open the
needle
valve counterclockwise to the
starting setting:
• 1-1/2 turns open
STARTING
14

5. Open the throttle approx. one-quarter.
6. Connect battery leads to glow plug.
7. Bring electric starter into contact with
spinner-nut or spinner and depress
starter switch for one or two seconds.
Repeat if necessary. When the engine
starts, withdraw the starter immediately.
Attention: Do not choke the carburetor air
intake when applying the starter.This could
cause an excessive amount of fuel to be
drawn into the cylinder which may initiate an
hydraulic lock and damage the engine.
If the engine does not start within 10 repeat
applications of the starter, remove the glow
plug, check that it glows brightly and that the
cylinder is not flooded with fuel. (To eject
excess fuel, close needle valve and apply
starter with glow plug removed.)Then try again.
VERY IMPORTANT! Before being operated
at full power (i.e. at full throttle and with the
needle-valve closed to its optimum setting)
the engine must be adequately run-in,
otherwise there is a danger of it becoming
overheated and damaged.
All internal-combustion engines benefit
from extra care when they are run for the
first few times known as running-in or
breaking-in.
This allows the working parts to mate together
under load at operating temperature.
Therefore, it is vitally important to complete the
break-in before allowing the engine to run
continuously at high speed and before
finalizing carburetor adjustments.
However, because O.S. engines are
produced with the aid of the finest modern
precision machinery and from the best and
most suitable materials, only a short and
simple running-in procedure is called for
and can be carried out with the engine
RUNNING-IN (“Breaking-In”)
15

installed in the model. The process is
as follows:
1. Install the engine with the propeller
intended for your model. Open the
needle valve to the advised starling
setting and start the engine. If the
engine stops when the glow plug
battery disconnected, open the needle
valve to the point where the engine
does not stop. Run the engine for one
minute with the throttle fully open, but
with the needle valve adjusted for rich,
slow "four-cycle" operation.
2. Now close the needle valve until the
engine speeds up to "two-cycle"
operation and allow it to run for about
10 seconds, then reopen the needle-
valve to bring the engine back to "four
cycle" operation and run it for another
10 seconds. Repeat this procedure
until the fuel tank is empty.
3. Re-start and adjust the needle-valve so
that the engine just breaks into "two-
cycle" from "four-cycle" operation, then
make three or four flights, avoiding
successive "nose-up" flights.
4. During subsequent flights, the needle
valve can be gradually closed to give
more power. However, if the engine
shows signs of running too lean, the
next flight should be set rich. After a
total of ten to fifteen flights, the engine
should run continuously, on its
optimum needle-valve setting, without
loss of power as it warms up.
5. After the completion of the running-in
adjust the carburetor at optimum setting
referring to “MIXTURE CONTROL
VALVE
ADJUSTMENT” section and
“
SUBSEQUENT READJUSTMENT”
section.
Optimum Needle Setting (1)
Slowly advance the throttle to its fully open
position, then gradually close the needle-
valve until the exhaust note begins to
change 4-cycle to 2-cycle). At this point,
16

disconnect the battery from the glow plug,
taking care that the battery leads or glow
plug clip do not come into contact with the
rotating propeller. If the engine stops when
the battery is disconnected, close the
needle valve about 30° and restart.
Optimum Needle Setting (2)
As the needle valve is closed slowly and
gradually, the engine RPM. Will increase
and a continuous high-pitched exhaust
note, only will be heard. Close the needle
valve 10-15° and wait for the change of
RPM. After the engine RPM increases turn
the needle valve another 10-15° and wait
for the next change of RPM.As the speed of
the engine does not instantly change with
needle-valve readjustment, small
movements, with pauses between, are
necessary to arrive at the optimum setting.
Note: This diagram is for reference
purposes only. Actual needle positions
may differ from those shown.
• To stop the engine, close the throttle
completely to cut off fuel/air supply.
NEEDLE-VALVE ADJUSTMENT DIAGRAM
17

18
IDLING ADJUSTMENT CHART

With the engine running, close the throttle
and allow it to idle for about five seconds,
and then open the throttle fully. If, at this
point, the engine is slow to pick up and
produces an excess of exhaust smoke, the
mixture is too rich. Correct this condition by
turning the Mixture Control Screw clockwise
15-30°. If the mixture is excessively rich,
engine RPM will become unstable: opening
the throttle will produce a great deal of
smoke and RPM may drop suddenly or the
engine may stop. This condition may also
be initiated by excessively prolonged idling.
If, on the other hand, the mixture is too lean,
this will be indicated by a marked lack of
exhaust smoke and a tendency for the
engine to cut out when the throttle is
opened. In this case, turn the Mixture
Control Screw counterclockwise 90° to
positively enrich the idle mixture, then turn
the screw clockwise gradually until the
engine regains full power cleanly when the
throttle is reopened.
Carry out adjustments patiently until the
engine responds quickly and positively to
the throttle control.
Note: Mixture Control Valve adjustments
should be made in steps of 15-30° initially,
carefully checking the effect, on throttle
response, of each small adjustment.
In the course of making carburetor
adjustments, it is just possible that the
Mixture Control Valve may be inadvertently
screwed in or out too far and thereby moved
beyond its effective adjustment range. Its
REALIGNMENT OF MIXTURE
CONTROLVALVE
MIXTURE CONTROL VALVE
ADJUSTMENT
19

basic setting can be re-established as
follows: Close the throttle rotor gradually
from the fully opened position until it is just
fully closed. (Do not turn further.) Then,
screw in the Mixture Control Screw until it
stops. Now unscrew the Mixture Control
Screw as indicated below.
Once the optimum needle-valve setting has
been established (see page 17, “NEEDLE-
VALVE ADJUSTMENT DIAGRAM”) the
procedure for starting may be simplified
as follows:
1. Open the needle valve one half-turn
(180°) from the optimum setting.
2. Set the throttle one-quarter open from the
fully closed position, energize the glow plug
and apply the electric starter.When the engine
starts, reopen the throttle and re-adjust the
needle valve to the optimum setting.
Note:When re-starting the engine on the
same day, provided that atmospheric
conditions have not changed
significantly, it may be practicable to re-
start the engine on its optimum
(running) setting.
Once the engine has been run-in and the
controls properly set up, it should be
unnecessary to alter the mixture settings;
except to make minor adjustments to the
Needle Valve occasionally, to take account
of variations in climactic conditions.
The use of a different fuel, however,
particularly one containing more, or less,
nitro methane and/or a different type or
proportion of lubricating oil, is likely to call
SUBSEQUENT READJUSTMENT
SUBSEQUENT STARTING PROCEDURE
20