O.S. Engines 21RG-X - Manual (Page 7)

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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.)
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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.
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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.
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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.