Fuel And Glowplug - O.S. engine MAX-21XM Owner's Instruction Manual

Linkage Bracket
FUEL
Use only top quality commercial model two-stroke engine fuel.
For consistent performance and long engine life, it is essential
to use fuel containing AT LEAST 18%(volumetric ratio)best-
quality lubricant. This engine is designed to run on both low
and high nitromethane content fuels, i.e. from mild mixtures
containing a few percent of nitromethane, up to high-speed racing
fuels containing 30%, or more, of nitromethane. Generally, power
output is increased-up to a certain point-as the nitromethane
content of the fuel is increased. As a starting point, we recommend
a fuel containing 10% nitromethane, changing to a fuel
containing more nitro if necessary. When the nitro content of the
fuel is increased or the brand of fuel is changed, it is advisable to
run the engine with a richer needle-valve setting, initially, so
that the optimum setting for the new fuel may be rechecked as
described in the RUNNING-IN paragraph.
Secure
3mm OD Outer Pipe
Throttle Servo
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 naked 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.
GLOWPLUG
The O.S. No.8 glowplug is recommended and one is supplied
with this engine. The MAX-21XM may not always run so well
with other types of plug.
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 becomes cooler and
ignition is retarded.
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.:
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