O.S. engine MAX-18CV-RMX Setup guide

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 vehicle, radio control equipment, etc.,
are accessible for checking at the same time.
●
●
1
CONTENTS
SAFETY INSTRUCTIONS AND
WARNINGS ABOUTYOUR O.S.ENGINE
ENGINE CONSTRUCTION, NOTES WHEN
APPLYING AN ELECTRIC STARTER
INSTRUCTIONS,
TOOLS, ACCESSORIES, etc.
BASIC ENGINE PARTS,
CARBURETOR CONTROLS (11J)
INSTALLATION
NOTES CONCERNING THE RECOIL STARTER
GLOWPLUG
STARTING THE ENGINE &
RUNNING-IN ('Breaking-in)
2-5
6-7
8-10
12-14
15 36
FINAL ADJUSTMENT
CARBURETOR CLEANLINESS,
CARE AND MAINTENANCE
CHECKING THE ENGINE,
TROUBLE SHOOTING
EXPLODED ENGINES VIEWS &
PARTS LIST
CARBURETOR EXPLODED VIEW &
PARTS LIST
O.S. GENUINE PARTS & ACCESSORIES
THREE VIEW DRAWING
30-33
11-12
16-20
34-35
21-22
23-25
25-29
37-38

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.
SAFETY INSTRUCTIONS AND WARNINGS ABOUTYOUR O.S. ENGINE
The advice which follows applies basically to ALL MODEL ENGINES and 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.
3
!

WARNINGS
Model engine fuel is poison-
ous.Donotallowittocomeinto
contactwiththeeyesormouth.
Always store it in a clearly
markedcontainerandoutofthe
reach of children.
Modelenginefuelisalsohighly
flammable. Keep it away from
open flame, excessive heat,
sources of sparks, or anything
else which might ignite it. Do
notsmokeorallowanyoneelse
to smoke, near to it.
Never operate your engine in an enclosed
space. Model engines, like automobile
engines, exhaust deadly carbon-monox-
ide. 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.

4
!

This engine was designed for model boats.
Donotattempttouseitforanyotherpurpose.
Mount the engine in your model securely,
following the manufacturers' recommenda-
tions, using appropriate screws and lock-
nuts.
Install an effective silencer (muffler).
Frequent close exposure to a noisy exhaust
(especially in the case of the most powerful
high-speed engines) may eventually impair
your hearing and such noise is also likely to
causeannoyancetoothers overawide area.
Take care that the glowplug clip or battery
leads do not come into contact with the pro-
peller or any other rotating parts. Also check
that the linkage to the throttle arm is secure.
If your engine does not have a built-in recoil
starter, use an electric starter. The wearing of
safety glasses is also strongly recommended.
When handling the boat immediately prior to
launching, be especially cautious.
Keep the propeller and other rotating parts
away from you.
NOTES
For their safety, keep all onlookers
(especially small children) well back (at
least 20 feet or 6 meters) when preparing
your model for running.
Before starting the engine, always check the
tightness of all the screws and nuts especial-
ly those of joint and movable parts such as
throttle arm. Missing retightening the loose
screws and nuts often causes the parts
breakage that is capable of harming you.
5
!

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.
Warning! Immediately after a glowplug-
ignition engine has been run and is still
warm, conditions sometimes exist whereby
it is just possible for the engine to abruptly
restart if it is rotated over compression
WITHOUT the glowplug battery being
reconnected.
NOTES
If your engine is equipped with a recoil
starter, pull the operating handle straight
out when starting the engine, so that the
cord does not rub against the hull or
engine. This will help prevent the cord from
being damaged by abrasion or engine
heat.
Do not extend the starter cord more than
45cm (18"). Do not abruptly release the
operating handle.
Allow the cord to rewind smoothly while still
holding the handle.
Do not attempt to disassemble the recoil
starter (if equipped). If you do so, the very
strong spring inside will be suddenly
ejected. This can be very dangerous.

6
Piston
Cylinder Liner
Crankshaft
ENGINE CONSTRUCTION
With this engine, the piston will
feel tight at the top of its stroke
(TDC) when the engine is cold.
This is normal.
The cylinder bore has a slight
taper.
The piston and cylinder are
designed to achieve a perfect
running clearance when they
reach operating temperature.
Near TDC
Slight taper
When the engine is cold. When the engine is hot.
7
NOTESWHEN APPLYING
AN ELECTRIC STARTER
Do not over-prime. This could
cause a 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.
We do not recommend running your boat
on the sea, or in any other saltwater
environment. Under such conditions, it is
difficult to prevent the engine from
becoming corroded and, eventually,
inoperative.
NOTE

8
Standard accessories
Glow Plug No.8
This manual handles the following two versions.
MAX- 18CV-RM with 11J carburetor
MAX- 18CV-RMX with 11J carburetor
MAX-18CV-RM & MAX-18CV-RMX INSTRUCTIONS
About the Head Gasket
These engines are equipped with two head
gaskets of 0.1mm thick and 0.2mm thick. It is
suggested to adjust the total thickness
according to atmospheric temperature,
humidity and glowplug used.
At early stage of running-in, when a glowplug
tends to burn out early or when high
nitromethane content fuel is used, try to run
the engine with both gaskets.
When low nitromethane content fuel is used,
try to run the engine removing the 0.1mm
gasket.
As delivered, the engine has the
carburetor lightly fit into its intake.
Secure it changing its angle
according to the hull.
NOTE
The O.S. "18CV-RM" is a high-perfor-
mance water-cooled marine engine for
small radio-controlled boats, especially
sport type hulls. A companion model, the
MAX-18CV-RMX incorporating a recoil
starter system is also available.
9
FUEL
Generally, it is suggested that the user selects a fuel
that is commercially available for model two-stroke
engines and contains 10-30% nitromethane. As a
starting point, we recommend a fuel containing 20%
nitromethane, changing to a fuel containing more
nitro if necessary. When the brand of fuel is changed,
or the nitro content increased, it is advisable to
repeat the running-in procedure referred to in the
RUNNING-IN paragraphs. Please note that with
high-nitro fuels, although power may
be increased for competition purposes,
glowplug elements do not last as long
and engine life will be shortened.
Items necessary for starting
!

!

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.
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the engine.
GLOWPLUG IGNITER
Commercialy available handy glowplug
heater in which the glowplug battery
and battery leads are integrated.
Fit a filter to the outlet tube of your
refuelling container to prevent entry of
foreign matter into the fuel tank.
SUPER FILTER (L) (Option)
PROPELLER
Use well balanced propellers only. As the ideal
diameter, pitch and shape vary according to the
size, weight and type of model, final selection
can be made after practical experiment. As a
starting point, suggested propeller
diameter is 36-40mm with a pitch/dia
ratio of 1.2-1.6 for Vee type hulls.

10
SILICONE TUBING
This is required for the connection
between the fuel tank and engine,
also for the water cooling system.
Inner dia. of 2.3mm and outer dia.
of 5Å`5.5mm would be suitable.
ELECTRIC STARTER AND STARTER BATTERY
Use a 12-volt electric starter
with suitable battery for start-
ing the engine.(18CV-RM)
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.
REMINDER!
TOOLS
HEX SCREWDRIVER
SCREWDRIVER
Necessary for engine installation.
1.5mm, 2mm, 2.5mm, 3mm
Necessary for carburetor adjustments.
No.1, No.2, etc
LONG SOCKETWRENCH 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.
!

NOTE
SOCKET DRIVER
Never use a propeller that has even a
slight damage.
Necessary for starting the engine.
It is suggested to keep a starter rope as a
reserve.
STARTER BELT
It is required to tighten and loosen the
carburetor retainer nut. Opposite side distance
of 6mm
11
18CV-RMX
18CV-RM
Water Cooled Head
Crankcase
Mounting Lugs
Cover Plate
Carburetor
Type 11J
Crankshaft
BASIC ENGINE PARTS
Starter Handle
Recoil Starter
Assembly No.5
Drive Hub Rear Adaptor
Glow Plug No.8 Glow Plug No.8
Water Cooled Head
Carburetor
Type 11J
Crankshaft Drive Hub
Crankcase
Mounting Lugs

12
CARBURETOR CONTROLS (11J)
The Needle-Valve:
The Mixture Control Screw:
The Throttle Stop Screw:
Three adjustable controls are provided on this
carburetor.
For adjusting the mixture strength when the throttle
is fully open.
For adjusting the mixture strength at part-
throttle and idle speed, to obtain steady idling
and smooth acceleration to mid speeds.
NOTE:
Readjustment may
be necessary, occa-
sionally to allow for
changes in fuel, gear
ratio or clutch en-
gagement point.
Needle Valve
Mixture Control Screw
Throttle
Stop Screw
For setting the minimum idle speed:
INSTALLATION OF THE CARBURETOR
As delivered, the engine has its carburetor
lightly installed into the intake boss. Secure it
as follows.
Loosen the retainer screw, rotate the
carburetor to its correct position and make
sure that it is pressed well down into the
intake boss, compressing the rubber gasket,
before retightening screw.
Rotate the retainer screw gently until it
stops, then tighten a further 60-90˚.
Do not overtighten the screw as this will
damage the carburetor body.
1.
2.
Rotate the retainer nut
gently until it stops. Tighten a further 60-90˚
13
INSTALLATION
Make sure that the engine mounting beams
in the hull are parallel, with their top
surfaces in the same plane. If they are not,
the engine will not rest firmly as the engine
mounting faces (undersides of the mounting
lugs) are precision machined to be flat and
in the same plane. Poor installation may not
only cause vibration, erratic running and
loss of performance, but may also damage
the engine itself by deforming the
crankcase, cylinder, etc.
The mounting beams and adjacent hull
structure should be as rigid as possible so
that the engine may develop its full
performance. Use 3mm steel screws, such
as Allen socket-head type, with locknuts, for
bolting the engine to the mounting beams.
1.
2.
3.If the holes in the mounting beams do not
align exactly with the engine's mounting
lugs, enlarge them slightly with a needle file
so that the mounting screws pass through
the holes smoothly without being forced.
Chamfer inside edges of bearers.

14
NOTES CONCERNING THE RECOIL STARTER
REMINDER!
Do not attempt to disassemble the recoil
starter. If you do so, the very strong
spring inside will be suddenly ejected.
This can be very dangerous.
Do not extend the starter cord more than
45cm(18"). Do not abruptly release the
operating handle. Allow the cord to
rewind smoothly while still holding the
handle.
Pull the operating handle straight out
when starting the engine, so that the
cord does not rub against the vehicle
body or engine.This will help prevent the
cord from being damaged by abrasion or
engine heat.
NOTE: Because, in the interests of
personal safety, dismantling of the starter
mechanism is strongly discouraged, the
Recoil Starter is available for replacement
only as a pre-assembled unit. However,
some related parts, such as Starting Shaft
and Rear Adaptor, are obtainable
separately. (See Parts List.)
Try to avoid spilling fuel over the starter
unit and its cord. Some fuels have a
detrimental effect on these parts.
The starter prevents the engine from
being rotated in the wrong direction. The
unit will be damaged if you attempt to
force the flywheel in the opposite
direction (i.e. clockwise when viewed
from the crankshaft end).
(18CV-RMX ONLY)
15
GLOWPLUG
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. An O.S. No.8 glowplug is supplied with the
engine. Another Recommended O.S. plug is A5 .
Carefully install plug finger-tight, before final tighten-
ing with the correct size plug wrench.
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items.
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.:
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, appropriately, fires the fuel/air charge
earlier; conversely, at reduced rpm, the plug become
cooler and ignition is retarded.
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.

16
STARTINGTHE ENGINE & RUNNING-IN ('Breaking-in)
The somewhat violent changes of hull attitude
that occur in running, combined with the fact
that, in boats the fuel tank is often located
some distance from the carburetor, means
that fuel 'head' at the carburettor can vary
and upset running.
Therefore,it is recommended that a muffler
pressurized fuel feed system be used.
PRESSURIZED FUEL SYSTEM
!

Before starting the engine, always check
the tightness of all the screws and nuts
especially those of joint and movable
parts such as throttle arm. Missing
retightening the loose screws and nuts
often causes the parts breakage that is
capable of harming you.
The following procedure is suitable for these
engines when the fuel containing up to 30%
nitromethane are used.
Fill the tank completely with fuel.
Temporarily remove the glowplug to check
that it glows bright red when energized.
Glow Plug Igniter
Pliers
Element glows when energized.
Replace the plug when the
element does not glow or is
burnt out.
17
Turn the needle-valve clockwise slowly until
it stops. This is the fully closed position.
Do not force to turn further.
Open the Needle-Valve 2 turns from the fully
closed position.
Open
Close
Needle Valve
Swith on the transmitter and make sure that
each linkage moves correctly.
Turn the engine with an electric starter or
recoil starter to draw fuel into the engine.
Fuel
Deliver fuel into the carburetor.
Fuel tank side
Throttle Trim
Raise the throttle trim 2 or 3 clicks on the
transmitter for easier starting.

18
Now connect glowplug battery lead to heat
the plug filament and start the engine.
Start the engine using an electric starter
making sure the engine rotation direction is
correct (counter-clockwise seen from the
crankshaft end).
In case of the 18CV-RMX
Starter Handle
Pull the starter handle briskly straight out
several times to start the engine.
When the engine starts, first repeat low
speed running and medium speed running
by raising and lowering throttle stick on the
transmitter to warm up the engine.
Aviod high speed running.
PRECAUTIONS
When starting the engine, with the hull out off the
water and no load on the engine, even below half
throttle, the engine can over-rev. Prolonged
running at higher throttle settings can result in
seizure of the connecting rod and crankpin. Never
run the engine with the throttle above the starting
setting with the hull out of the water and no load
on the engine.
19
Next, disconnect the glowplug battery and
try running the hull on the water. If the
engine stalls, open the throttle fractionally,
but try to keep the engine running as rich as
possible: if it stops because of being
excessively over-rich, close the Needle-
Valve 30˚and try again.
Runthe hull on the water until one tank of fuel
has been consumed, then close the Needle-
Valve 30˚and run the hull for another full tank
of fuel. Repeat this procedure until 5 more
tanks of fuel have been consumed, during
whichtimethethrottlemaybeopenedforbrief
bursts of increased power.
If the engine stops at medium speeds, close
the Mixture Screw 45-90˚.
Needle
The position of the needle-valve
when starting the engine.
Close the needle-valve approx.
30˚after running the hull for
one full tank of fuel.
Repeat this procedure several
times.
If the engine should need to be
disassembled (e.g. for cleaning or minor
parts replacement) it is advisable to return
the Needle-Valve to the original rich,
starting setting and check whether further
running-in time is required before the car is
raced again. In the event of any major
working parts(e,g, piston/cylinder liner
assembly) being replaced, the complete
running-in should be repeated.
Remember!

20
Warning!
Do not touch rotating parts, engine and si-
lencer when stopping the engine as they
become very hot, and contact with them
may result in a serious burn.
Throttle Trim
Throttle Stick
TO STOP THE ENGINE
Lower the throttle trim and/or throttle stick on
the transmitter.
21
Run the hull (with throttle fully open) over the
longest available straight, in order to observe
the model's speed. Next return the hull to the
starting point, close the Needle-Valve 30˚
and repeat the run, taking note of the
improvement in performance. Continue with
further runs, gradually reducing the Needle-
Valve setting and aiming to achieve the
highest straight-line speed. Remember,
however, that, if the Needle-Valve is shut
down too far, the engine will overheat and,
accompanied by visibly diminished exhaust
smoke, the model will lose speed. At this
point, throttle down immediately, stop the hull
and reopen the Needle-Valve 30˚.
With the engine running, close the throttle
and allow it to idle for about five seconds,
then reopen the throttle fully. If, at this point,
the engine puffs out an excessive amount of
smoke and the hull does not accelerate
smoothly and rapidly, it is probable that the
idle mixture is too rich.
FINAL ADJUSTMENT
Having established the optimum Needle-
Valve setting, check the Mixture Control
Valve setting as follows.
In this case, turn the Mixture Control Valve
clockwise 45-90˚. If, on the other hand, the
engine tends to speed up momentarily and
then cut out abruptly when the throttle is
opened,the idle mixture is too lean. Correct
this by turning the Mixture Control Valve
counter-clockwise 45-90˚.
NOTE:
Mixture Control Valve adjustment should
be made in steps of not more than 45-90˚,
carefully checking the effect,on throttle
response, of each small adjustment.

22
Warning!
Carry out adjustments patiently, under
actual running conditions, until the engine
responds quickly and positively to the
throttle control.
Mixture adjustments (whether via the
Mixture Control Valve, or the Needle-Valve)
cannot be made accurately under 'no-load'
conditions, which, in any case, are not
advised, since such operation carries the
risk of seriously damaging the engine
through over-revving and overheating.
With the optimum mixture control position,
light smoke is visible during high speed
running,and the engine rpm increases
smoothly during acceleration. Remember
that, if the engine is operated with the fuel/air
mixture slightly too lean, it will overheat and
run unevenly. As with all engines, it is
advisable to set both needle-valve and
mixture control screw very slightly on the rich
side of the best rpm setting, as a safety
measure.
If the engine runs too fast with the throttle
closed, the throttle stop screw should be
turned counter-clockwise to allow the throttle
opening to be reduced.
Finally, beyond the nominal break-in period,
a slight readjustment toward a leaner needle
setting may be required to maintain
performance.
23
REALIGNMENT OF MIXTURE CONTROL VALVE
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 basic position can be found by first rotating
the Mixture Control Valve until its slotted head
is flush with the carburetor body.
The valve is then screwed in exactly 0.5 turns
to re-establish its neutral position.
Carburetor Body
Mixture Control Screw
First rotate the Mixture Control
Screw until its slotted head is
flush with the carburetor body.
Then screw the valve in
exactly 0.5 turn.
This is the standard position.
Throttle Lever
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on its small fuel orifices remaining clear.
NOTE:
It is necessary to readjust the needle-valve
when the plug, propeller, fuel, silencer, etc.
are changed. Also, needle setting varies to
atmospheric conditions (temperature,
humidity, pressure) even in the same day.
Readjust the needle if necessary watching
the engine running conditions.

24
CARE AND MAINTENANCE
Engine maintenance is very important for good
running next time. Carry out the followings.
As previously observed, foreign matter in
the fuel can cause problems. Therefore:
rinse out the fuel tank with methanol or fuel
before installing it.
Install a fuel filter to the fuel delivery tube
between tank and carburetor.
Install a fuel filter to the outlet of your
squeeze bottle, or to the pump inlet if you
use a manual or electric pump. *
do not leave your fuel container open
needlessly.
O.S. ' Super-Filter ' (L) is available, as op-
tional extra,to deal with this problem. To fit
this filterto the outlet tube inside your refuel-
ling container, will prevent the entry of for-
eign material into the fuel tank.
Do not forget to clean the filters regularly to
remove dirt and lint that accumulate on the
filter screens. Also, clean the carburetor
itself occasionally.
1.
2.
At the end of each operating session, drain
out any fuel that may remain in the fuel tank.
Afterwards, energize the glowplug and try to
restart the engine, to burn off any fuel that
may remain inside the engine. Repeat this
procedure until the engine fails to fire. Leav-
ing fuel residues within the engine can result
in difficult starting after a period of storage. It
may also cause corrosion. To reduce such
risks, it is helpful to inject some corrosion in-
hibiting oil into the engine's air intake. Rotate
the engine many times to distribute the oil to
all the working parts.
3.
25
Drain the water remaining in the water cool-
ing head, and wash out with methanol, then
inject corrosion-inhibiting or moisture-dis-
placing oil.
When cleaning the exterior of the engine,
use methanol or kerosene. Do not use ga-
soline or any solvent that might damage the
silicone fuel tubing or any plastic parts of the
boat hull.
When the engine is not in use remove the
glowplug and rinse out the interior with kero-
sene (not gasoline), by rotating the crank-
shaft. Shake out residue, then inject light
machine-oil through the plug hole again ro-
tating the shaft to distribute the protective oil
to all working parts.
4.
5.
6.
In the event of water having entered the cy-
linder, crankcase, etc., refer to the proce-
dures recommended in the footnote to
"running-in" section.
7.
8.
After long use, the engine will not develop the
standard performance due to wear of parts. It
is suggested to replace the parts, such as ball
bearings, connecting rod, cylinder & piston
assembly and crankcase, as necessary after
checking when the following symptoms are
found.
CHECKING OFTHE ENGINE
Idling gets unstable and/or the engine stops
at idling.
Engine sound changes and the engine tends
to overheat.
Power drops extremely.
Avoid unnecessary disassembly of your en-
gine.

26
TROUBLE SHOOTING
Symptom
Cause Corrective action
Engine fails to fire.
Fuel tank is empty.
Fuel not reaching the engine. Fill the tank with fuel and repeat
Priming procedure.
Glowplug element is burnt out.
Glowplug battery discharged Replace glowplug. Recharge or replace the battery.
Clogged fuel filter
Silencer inside is dirty. Clean or replace fuel filter.
Clean inside the silencer.
Over priming Remove glowplug and pump excess fuel.
Fuel tubing is disconnected. Connect fuel tubing securely.
Fuel tubing is kinked, split or has a hole.
Check the tubing carefully and replace if necessary.
Incorrect servo linkage Connect correctly after setting servo at neutral.
Reverse rotating direction of electric starter. Mare sure it rotates counter clockwise seen
from crankshaft side.
Recoil starter slips. Inject cleaner spray into starter cord crevis
on the body.
27
Symptom
Cause Corrective action
Engine fires intermittently but does not run.
Insufficient fuel in the tank. Fill the tank with fuel.
Deteriorated glowplug Replace glowplug.
Clogged fuel filter
Silencer inside is dirty. Clean or replace fuel filter.
Clean inside the silencer.
Engine overheated Wait until engine cools.
Glowplug battery disconnected too soon. Do not disconnect plug battery and wait until
r.p.m. become stable.
Air bubbles in fuel Install O rings to the tank screws to
prevent bubbles.

28
Symptom
Cause Corrective action
Symptom
Cause Corrective action
Unstable idle
Unsuitable glowplug Use suggested glowplug in the instructions.
Unsuitable fuel Do not use extremely high nitro or
low oil content fuel.
Extremely light flywheel Add suitable load.
Silencer is disconnected or has play Install silencer securely.
Not reaching expected peak r.p.m.
Insufficient warming up or running-in. Set the needle only after warming up.
Complete running-in.
Silencer or manifold is not securely connected
or disconnected. Replace seal ring.
Check the connections and secure them.
Fuel tubing from tank is split or broken. Replace the tubing.
29
Symptom
Cause Corrective action
Symptom
Cause Corrective action
Poor response
Deteriorated glowplug Replace glowplug.
Incorrect carburetor settings Readjust low r.p.m.range with metering
needle and mixture control valve.
Incorrect setting of transmitter Exponential function. Check the transmitter setting.
Poor r.p.m. drop
Throttle position open too far.
Incorrect carburetor installation Install carburetor properly.
Lower the throttle trim on the transmitter.
Too much closing of the needle-valve
and/or mixture control screw. Open the needle-valve an/or mixture control
screw a little.

30
1
2
3
46
11 12
13
5
7
910
14
C.M2.6x7
15
8
16
C.M2.6x18
18CV-RM EXPLODED VIEW
Type of screw
C...Cap Screw M...Oval Fillister-Head Screw
F...Flat Head Screw N...Round Head Screw S...Set Screw
31
18CV-RM ENGINE PARTS LIST
The specifications are subject to alteration for improvement without notice.
21804100
21824000
21823000
21816000
21817000
21815000
21884000
21818000
20810007
21408000
21833000
21811000
21832000
21812000
21807100
21213030
71608001
Description
Code No.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Water Cooled Head Assembly
Gasket Set
Cylinder & Piston Assembly
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete (Type 11J)
Carburetor Retainer Assembly
Propeller Nut
Drive Hub
Crankshaft Ball Bearing (Front)
Crankcase
Crankshaft Ball Bearing (Rear)
Crankshaft
Cover Plate
Screw Set
Glow Plug No.8

32
16
18
18-1
18-2
1
2
3
46
11
12
13
5
7
910
14
15
8
17
C.M2.6x18
M.+M2.6x7
M.+M2.6x7
18CV-RMX EXPLODED VIEW
Type of screw
C...Cap Screw M...Oval Fillister-Head Screw
F...Flat Head Screw N...Round Head Screw S...Set Screw
33
18CV-RMX ENGINE PARTS LIST
The specifications are subject to alteration for improvement without notice.
21804100
21824000
21823000
21816000
21817000
21815000
21884000
21818000
20810007
21408000
21833000
21811000
21832000
21812100
21812200
21801800
21213020
73003000
73003100
73003200
71608001
Description
Code No.
No. Water Cooled Head Assembly
Gasket Set
Cylinder & Piston Assembly
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete (Type 11J)
Carburetor Retainer Assembly
Propeller Nut
Drive Hub
Crankshaft Ball Bearing (Front)
Crankcase
Crankshaft Ball Bearing (Rear)
Crankshaft
Starting Shaft
Rear Adaptor
Screw Set
No.5 Recoil Starter Assembly
No.5 Recoil Starter Body
No.5 One-way Clutch
Glow Plug No.8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
18-1
18-2

34
1
1-1
1-2
3
45
2
10
67
8
9
9-1
11J CARBURETOR EXPLODED VIEW
35
11J CARBURETOR PARTS LIST
The specifications are subject to alteration for improvement without notice.
Description
Code No.
No. Needle Valve Assembly
"O" Ring (2pcs.)
No.14 Universal Nipple Assembly
Throttle Stop Screw
Carburetor Body
Rotor Spring
Carburetor Rotor
Dust Cover
Throttle Lever
Throttle Lever Fixing Nut
Mixture Control Screw
"O" Ring (2pcs.)
Carburetor Rubber Gasket
21285901
27881820
21881950
22681310
21884100
22481506
21884200
21283210
22681419
21481420
21484600
27881820
22615000
1
1-1
1-2
2
3
4
5
6
7
8
9
9-1
10

36
(72103310)
(71605300)
A3
(71605100)
A5
(73300305)
(73301612)
(79871020)
(79871055)
(71521000)
(21342000)
(55500002)
3.5mm
(72403050)
M3
O.S. GENUINE PARTS & ACCESSORIES
GLOW PLUG
LONG SOCKETWRENCH
WITH PLUG GRIP
SUPER FILTER
LOCKWASHER
MARINE UNIVERSAL
JOINT
DUST CAP SET
(L)
(10sets)
SUPER JOINT TUBE 15
3
16
For Carburetor Nipple
For Carburetor
CAP SCREW SET
M2.6x7
(10pcs. set)
M2.6x18
(5 pcs. set)
(3 pcs. set)
The specifications are subject to alteration for improvement without notice.
37
■
■
■
■
■
■
M5x0.8
11
31.4
39
25 15
41
69
25
27.5
50.5
18CV-RM W/11J THREE VIEW DRAWING
SPECIFICATIONS
Displacement
Bore
Stroke
Practical R.P.M.
Power output
Weight
Dimensions(mm)
3.0 cc (0.183 cu.in.)
16.0mm (0.629 in.)
15.0mm (0.590 in.)
3,000-32,000 r.p.m.
1.35 ps / 28,000 r.p.m.
175.5g (6.2oz.)

38
M5x0.8
33.8
40 41 87.8
25
27.5
11
31.4
50.5
3.0 cc (0.183 cu.in.)
16.0mm (0.629 in.)
15.0mm (0.590 in.)
3,000-32,000 r.p.m.
1.35 ps / 28,000 r.p.m.
232.6g (8.21oz.)
18CV-RMX W/ 11J THREE VIEW DRAWING
SPECIFICATIONS
Displacement
Bore
Stroke
Practical R.P.M.
Power output
Weight
Dimensions(mm)
C Copyright 2005 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
TEL.[phone]
FAX.[phone]
6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
U
N
E
Q
U
A
L
L
E
D
Q
U
A
L
I
T
Y
P
R
E
C
I
S
I
O
N
&
P
E
R
F
O
R
M
A
N
C
E
E
S
T
A
B
L
I
S
H
I
N
G
T
H
E
S
T
A
N
D
A
R
D
S
O
F
E
X
C
E
L
L
E
N
C
E
URL : http://www.os-engines.co.jp
60091580 020500