Jets Munt Merlin M166TS, Instruction Manual

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The kerostart system used on this engine is a reliable and well tested system that produces very
smooth and trouble free starts.
However, extra care and attention must be paid when starting a kerostart engine.
The main difference between gas and kerosene is that in the case of a failed ignition, the gas
dissipates quickly on the air and don't keep inside the engine. Kerosene is liquid and, if
unburned, will pool inside the engine and stay there forever. The engine can hold a big quantity
of kerosene inside. This kerosene will be ignited on next successful start up and will be pushed
to the exhaust as soon as the airflow inside the engine is sufficient, then it will be ignited in the
exhaust, causing a hot start (in extreme cases a big fireball) that surely will not hurt the engine,
but can destroy the model.
To prevent this:
-During the start-up listen to the engine sound to check for positive sound of
ignition, check looking from the exhaust that the kero is burning, or check for an
increase in exhaust temperature in the data terminal. A small plume of white smoke
from the exhaust means that the fuel is not burning. The fuel is pooling inside the
engine. Abort immediately the start.
-Double check that the engine is not flooded. An extra security measure is to
place a manual valve between the last fuel tank and the pump intake line, to prevent
that during the process of filling the tanks or during storage, some fuel can arrive to the
engine.
-After a failed start, or whatever condition that could cause that fuel be
collected inside the engine (i.e. extra priming), ALWAYS empty the engine of fuel by
tilting the engine nose down. Fuel will exit trough intake. Do not tilt upwards; due at
the internal engine construction the fuel cannot exit trough exhaust.
Another big difference between gas start and liquid start is that the kerosene can keep burning
slowly during long time inside the engine. This situation usually happen during an aborted
start, the start-up sequence is aborted by the user or automatically before the engine arrive to
idle. This can cause that the kerosene inside the engine keep burning for long time, and could
destroy the engine or the model. IF A STARTUP SEQUENCE IS NOT COMPLETED, ALWAYS
CHECK FOR FLAME INSIDE THE ENGINE. If there is flame, then set full throttle for over 3
seconds to engage the starter and blow out the flame. USE SHORT BURSTS OF STARTER. Using
the starter for long time can destroy the starter motor. In the case that the start-up procedure
has been aborted due at starter failure, then it will be necessary to apply the CO2 fire
extinguisher. A white smoke plume from the engine is a good indication here; mean that there
is no fire inside.
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