19/04/2019
V2.0
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5.4 Spark plug diagnosis
During the run-in time a wet and tarry spark plug is a good sign because it means that
the mixture is rich. Petrol in a two-stroke engine is not only a fuel, but also a heat
conductor, which is emitted excessively during the run-in. During the run-in time, we advise
you to error on the side of caution and use a rich mixture at the expense of slightly weaker
engine performance.
During the run-in time it is generally recommended to use the engine on differential
speed and not to keep one speed for a long time (e.g. long flight on a steady altitude).
Manipulating gently with the gas throttle during the run-in and acting according to the
guidelines described above will lead to sustained and trouble-free engine running and
significantly prolong the amount of time before the first repair. If the user intentionally does
not follow the guidelines presented above, it will cause the loss of any warranty rights or the
engine’s damage. It is important to bear in mind that preserving the engine in the best
shape during further exploration depends on how we handle it in the first hours.
The run-in time for the “Nitro 200” or “Tornado 280” engine is about 10 hours of flight.
The practical way of estimating the length of run-in stage is using up 1 liter bottle of oil.
We advise you to mount a tachometer, which facilitates both evaluating the engine’s
state for basic adjustments and serves as an hour meter.
1
Mixture is too lean
– it could damage
the engine
2
Mixture is rich, but
correct for the run-
in time
3
Optimal mixture
(dark grey or
chocolate color)
4
New spark plug –
for comparison
