O.S. Engines Rotary 49PI User Manual
Page 16
RUNNING-IN ("Breaking-in")
For running-in, fit the engine with a well-bal-
anced propeller intended for actual flight. Use
a fuel mixture as specified. Running-in proce-
dure is the same as for a conventional recipro-
cating model engine. After starting the motor,
open the throttle fully, but use a rich needle-
valve setting to reduce rpm, increase lubrica-
tion and lower running temperature. This will
produce a smoky exhaust but will ensure that
the engine does not become overheated and
damaged during this critical period.
The break-in should be split up into periods of
not more than 5 minutes, allowing the engine
to cool between spells of running. After about
30 minutes' running time have been accumula-
ted, the needle valve may be gradually closed
on each succesive run until continuous full-
power is being delivered. This is with the nee-
dle-valve set slightly rich of the setting at which
maximum speed is reached. If the engine
shows signs of slowing-up and overheating,
immediately reopen the needle-valve and con-
tinue the running-in process.
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