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12

FURTHER PRECAUTIONS

When removing the air cleaner, check the inside of the 
center tube and carburetor venturi. If any dirt is detected, 
this indicates that the filter element was incorrectly 
installed or should have been replaced earlier.In this 
event, it is vitally important to wash out the inside of the 
engine thoroughly, with alcohol or fuel,before it is used 
again, otherwise rapid wear of the piston, 
cylinder,bearings, connecting-rod, etc., will occur. 
Obviously, it will be necessary to carry out the same 
procedure with the air cleaner and to replace the filter 
element.
NOTE: Be careful not to splash alcohol or fuel 
over the filter element, or the filter oil will be 
diluted, and the filter capacity lowered.

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.

This will help prevent the cord from being 
damaged by abrasion or engine heat.

Try to avoid spilling fuel over the starter unit and 
its cord. Some fuels have a detrimental effect on 
these parts.

Pull the operating handle straight out when 
starting the engine, so that the cord does not 
rub against the vehicle body or engine. 

The starter prevents the engine from being ro-
tated 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).

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.)

13

GLOWPLUG

Glowplug life

Particularly in the case of very high performance 
engines, glowplugs must be regarded as expendable 
items. 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 
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. 


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.

TOOLS, ACCESSORIES, etc.

The following items are necessary for operating the 
engine.

Generally, it is suggested that the user selects a fuel that 
is commercially available for model two-stroke eengines 

FUEL

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. Other Recommended O.S. plugs are A3 and 
A5. Carefully install plug finger-tight, before final tight-
ening with the correct size plug wrench.

Summary of Contents for MAX-21RG Series

Page 1: ...ontrol equipment etc are accessible for checking at the same time 1 2 5 6 7 8 8 9 12 12 13 15 15 18 21 23 24 27 28 29 30 13 14 21 22 18 19 20 SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE INTRODUCTION BASIC ENGINE PARTS INSTALLATION OF THE CARBURETOR INSTALLATION OF THE ENNGINE AIR CLEANER TYPE201 NOTES CONCERNING THE RECOIL STARTER GLOWPLUG TOOLS ACCESSORIES etc CARBURETOR CONTROLS START...

Page 2: ...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 poi sonous Do not allow it to come into contact with the eyesormouth Alwaysstore it in a clearly marked con tainer and out of the reach of children Model engine fuel is also...

Page 3: ...aring your model for running NOTES 5 NOTES To stop the engine fully retard the throttle stick and trim lever on the trans mitter or in an emergency cut off the fuel supply by pinching the fuel delivery tube from the tank 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...

Page 4: ...ne is cold This is normal The piston and cylinder are designed to achieve a perfect running clearance when they reach their normal running temperatures BASIC ENGINE PARTS Carburetor Crankshaft Crankcase Beam Mount Recoil Starter Assembly No 5 Heatsink Head Starter Handle 7 ENGINE INSTALLATION Make sure that the vehicle s engine mounting surfaces are level and in the same plane Poor installation ma...

Page 5: ...oss compressing the rubber gasket before retightening screw Rotate the retainer screw gently until it stops then tighten a further 90 120 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 90 120 9 AIR CLEANER TYPE 201 This is a heavy duty wet type air cleaner that has been developed specifically for 3 5cc off ro...

Page 6: ...andsecurewithstrap supplied Fit the other end of the elbow over the carburettor intake and secure with strap supplied Do not use glue at this point It is advisable to brace the outer end of the air cleaner to the car chassis with a piano wire strut This will restrain the cleaner in the event of the vehicle overturning or being involved in a collision Under very dusty conditions it is advisable to ...

Page 7: ...ted parts such as Starting Shaft and Rear Adaptor are obtainable separately See Parts List 13 GLOWPLUG Glowplug life Particularly in the case of very high performance engines glowplugs must be regarded as expendable items 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 nitrome...

Page 8: ...ro content increased it is advisable to repeat the running in procedure referred to in the RUNNING IN paragraphs For consistent performance and long engine life it is essential to use a good quality fuel containing NOT LESS THAN 18 lubricant Please note that with high nitro fuels although power may be increased for competition purposes glowplug elements do not last so long and engine life will be ...

Page 9: ... will under these conditions provide adequate lubrication and cooling indicated by profuse smoke from the exhaust Next disconnect the glowplug battery and try running the car on the track 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 Run the car on...

Page 10: ...t is probable that the idling mixture is too rich FINAL ADJUSTMENT 19 In this case turn the Mixture Control Valve clockwise 30 If on the other hand the engine tends to speed up momentarily and then cut out abruptly when the throttle is opened the idling mixture is too lean Correct this by turning the Mixture Control Valve counter clockwise 30 45 Warning NOTE Mixture Control Valve adjustment should...

Page 11: ...by hand It should rotate smoothly Now turn the engine with an electric starter until fuel is drawn into the carburetor At first rotation may feel sticky due to oily residue remaining within the engine The engine should rotate freely after fresh fuel has been drawn into the working parts Check the glowplug If the plug element is distorted off center or has a white appearance engine performance may ...

Page 12: ...48 F otherwise it may be damaged and rendered unserviceable GUARANTEE This engine is constructed from the very best materials available and to the very highest engineering standards using the most advanced precision machinery However the extremely high stresses imposed by car racing operation under very severe conditions stresses which are exacerbated by the use of powerful fuels containing very h...

Page 13: ...41614000 23601000 23626100 22830000 23602000 23602010 23614000 23607000 22447005 72411000 72411020 72411050 72411010 72411040 72411030 71608001 Description Code No No Center Tube Intake Elbow Center Screen Element Plate Set Comprising 201 Filter Elements 4pcs Super Air Cleaner 201 W two filter elements Screw Set Cover Plate Gasket Set Crankshaft Ball Bearing Rear Exhaust Adaptor No 5 Crankcase Cra...

Page 14: ...0 23614000 23602050 23601800 22447005 73003000 73003100 73003200 72404110 72411000 72411020 72411050 72411010 72411040 72411030 71608001 Center Tube Intake Elbow Center Screen Element Plate Set Comprising 201 Filter Elements 4pcs Super Air Cleaner 201 W two filter elements Screw Set Gasket Set Crankshaft Ball Bearing Rear Crankcase Crankshaft Ball Bearing Front Carburetor Retainer with screw Carbu...

Page 15: ...3 4 4 5 6 7 8 9 10 11 23818180 46066319 22781800 23818500 23618190 23618197 46066319 23618194 23818176 23618102 45581820 23818251 23818310 23818220 22884220 23818400 29015019 Description Code No No Carburetor Rubber Gasket Ball Link No 1 Dust Cover Slide Valve Extension Metering Needle Assembly Slide Valve Slide Valve Guide Screw Carburetor Body Universal Nipple No 9 Needle Holder Assembly O Ring ...

Page 16: ...nsions mm THREE VIEW DRAWING Displacement Bore Stroke Practical R P M Power output Weight SPECIFICATIONS C Copyright 2000 by O S Engines Mfg Co Ltd All rights reserved Printed in Japan 60091020 050403 TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan URL http www os engines co jp U N E Q U A LLED QUALITY PRECISION PERFOR M A N C E E S T A BLISHING THE ...

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