O.S. engine MAX-105HZ-R Instruction Manual page 19

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Please pay attention to the matters
described below to ensure that your engine
serves you well in regard to performance,
reliability and long life.
e As previously mentioned, it is vitally important
to avoid operating the engine in conditions
where dust, disturbed by the rotor, may be
deposited on the engine and enter its working
parts.
e Remember to keep your fuel container
closed to prevent foreign matter from
contaminating the fuel.
e Install a fuel filter to prevent foreign matter in
the fuel container from entering the fuel tank.
O.S. Super Filters (L) and (S) are available
as optional extras.
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e Do not close the needle-valve and mixture
control valve too far as this will cause a lean
setting and over heating of the engine. This
can, in turn, create nitromethane oxide
leading to internal rusting of the engine.
Always adjust the needlevalve slightly on the
rich side of peak rpm.
e Do not leave unused fuel in the engine at the
conclusion of a day's flying. Accepted
practice is to cut off the fuel supply while the
engine is still running at full throttle, then
expel as much fuel residue as possible by
turning the engine over 5-10 seconds with
the electric starter.
Finally, inject some after-run oil through the
glowplug hole and turn the engine over
several times by hand.
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CARE AND MAINTENANCE
e Install an in-line fuel filter between the tank
and carburetor to prevent foreign matter in
the tank from entering the carburetor.
e Clean these filters periodically.
e |f these precautions are neglected, restriction
of fuel flow may cause the engine to cut out,
or the fuel/air mixture to become too lean
causing the engine to overheat.
e The use of modern high-performance alcohol
based model engine fuels, while promoting
cooler running, improved anti-detonation
combustion and increased power, have the
disadvantage of causing corrosion due to the
acid by-products of combustion.
The use of nitromethane in the fuel can also
contribute to the problem.
e When the engine is not to be used for some
months (for example, as between flying
seasons), a worthwhile precaution is to
remove it from the airframe and, after
washing off the exterior with alcohol (not
gasoline nor kerosene), remove carefully the
carburetor with intake pipe, glow plug and all
silicone tubing and put them safely aside.
Then, immerse the engine in a container of
alcohol. Rotate the crankshaft while the
engine is immersed. If foreign matter is
visible in the alcohol, rinse the engine again
in clean alcohol. Finally, shake off and dry
the alcohol, and inject some after-run oil in
the glowplug hole and rotate the crankshaft
several times by hand.
Reinstall the carburetor with intake pipe and
glowplug on the engine and keep it in a dry
place after putting in a vinyl bag.