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It is of vital importance, before attempting to operate your 

engine, to read the general 'SAFETY INSTRUCTIONS 

AND WARNINGS' in the following section 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.

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

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.

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 or abused. 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.

WARNINGS

NOTES

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.
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 operate your engine in an enclosed space. 

Model engines, like automobile engines, exhaust 

deadly carbon-monoxide. Run your engine only in 

an open area.

Install an effective silencer (muffler). Frequent close 

exposure to a noisy exhaust (especially in the case 

of the more powerful highspeed engines) may 

eventually impair your hearing and such noise is 

also likely to cause annoyance to others over a wide 

area.

The wearing of safety glasses is also strongly 

recommended.
Take care that the glowplug clip or battery leads do 

not come into contact with rotating parts. Also check 

that the linkage to the throttle arm is secure. 
For their safety, keep all onlookers (especially small 

children) well back (at least 20 feet or 6 meters) 

when preparing your model for running.

This engine is intended for model cars. 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.

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 

line 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 is rotated over compression WITHOUT the 

glowplug battery being reconnected.

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. 

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.

Piston

Cylinder

Liner

Crankshaft

Near TDC

Slight taper

When the engine is cold. When the engine is hot.

NOTES WHEN 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 any pumped out fuel from getting into 

your eyes.

As delivered, the engine has the carburetor 

lightly fit into its intake. Secure it changing its 

angle according to the car chassis.

NOTE

Please do not run on a public street, this could 

cause serious accidents, personal injuries 

and/or propetry damage.

Please do not run near pedestrians or small children.
Please do not run in small or confined areas.
Please do not run where loud noises can disturb 

others, such as hospitals and residential areas.

While Operating

ABOUT THE ENGINE

FUEL

Generally, it is suggested that the user selects a fuel that is 

commercially available for model two-stroke engines 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

TOOLS, ACCESSORIES, etc.

The following items are necessary for operating the engine.

FUEL FILTER

To installed in the fuel line between fuel 

tank and carburetor to prevent foreign 

matter from entering the carburetor.

GLOWPLUG IGNITER

Commercialy available handy glowplug 

heater in which the glowplug battery and 

battery leads are integrated. 

STARTER BOX

For starting the engine.

FUEL PUMP

For filling the fuel tank, a simple, polyethylene 

"squeeze" bottle, with a suitable spout, is 

required. 

TOOLS

O.S. SPEED DRIVER TOOLS

O.S. SPEED PLUG WRENCH

O.S. SPEED

CLUTCH WRENCH & ADJUSTER

O.S. SPEED FLYWHEEL KEY

O.S. SPEED FLYWHEEL PULLER

ABOUT THE WARRANTY

NOTES ON OPERATION

Since this is a special SPEED version, individual 

special parts are available only for limited period 

(one year after finishing the production).

Also, the engine is free of warranty due to damage 

and/or wear occurred during running.

We have developed this new model working with Adam 

Drake one of top drivers in OS international team, 

based on B2101, while we apply 21J3(B) carburetor of 

OS SPEED 21XZ-B SPEC 3. 

The piston/sleeve and the crankshaft are completely 

new design. Piston stroke is 16.55mm, and the 

double-tungsten counter weighted crankshaft produces 

more torque.  So the engine is not just a combination of 

existing models’ parts but a new model. 

The standard accessories, 6.5mm reducer is for buggy 

and 8.0mm for truggy, and glow plug is OS SPEED P3 

GOLD for better fuel consumption.

Exhaust Seal Ring  1piece

Dust Cap   3,  16,  18  1piece each 

Carburetor Reducer    6.5 (BLUE) 

(w/ "O" Ring)

   

1piece

Standard accessories

The connection between the fuel tank and the engine. 

2.5mm ID

O.S. SPEED SILICONE FUEL LINE (optional extra)

Carburetor Reducer    8 (BLUE) 

(w/ "O" Ring)

   

1piece

O.S.SPEED T-Series Glow Plug P3

(Hot Type)  1piece

Summary of Contents for B21 ADAM DRAKE EDITION

Page 1: ...able parts such as throttle arm Missing retightening the loose screws and nuts often causes the parts breakage that is capable of harming you 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 rea...

Page 2: ... retightening screw 1 2 Rotate the retainer nut gently until it stops Rotate the retainer screw gently until it stops then tighten a further 120 180 Do not overtighten the screw as this will damage the thermo insulator Tighten a further 120 180 Note Be careful not to damage the O rings when removing the carburetor retainer from the engine First remove the retainer Retaining screw then pull out eac...

Page 3: ...EED DRIVER TOOLS Code No Description 71414015 71414020 71414025 71414030 71414120 71414125 71414230 71414355 71414360 71414370 O S SPEED HEX WRENCH TIP ONLY 1 5 O S SPEED HEX WRENCH TIP ONLY 2 0 O S SPEED HEX WRENCH TIP ONLY 2 5 O S SPEED HEX WRENCH TIP ONLY 3 0 O S SPEED HEX BALL WRENCH TIP ONLY 2 0 O S SPEED HEX BALL WRENCH TIP ONLY 2 5 O S SPEED FLAT HEAD SCREWDRIVER TIP 3 0 O S SPEED NUT DRIVE...

Page 4: ...od w piston pin retainers 3pcs Carburetor Complete Type 21J3 B Carburetor Retainer Assembly O Ring 2pcs Crankshaft Ball Bearing Front Crankcase Ceramic Ball Bearing Rear Crankshaft Cover Gasket Cover Plate Glow Plug O S SPEED P3 Reducer 6 5mm BLUE AL2 Reducer 8mm BLUE AL Exhaust Seal Ring 21 10pcs O S SPEED Dust Cap Set For 12 30 Class No Code No Description Displacement Bore Stroke Output Practic...

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