5.4 Typical spark plug hues are shown below
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 warmth
conductor, which is emitted excessively during the run-in. During the run-in time, we even
advise you to use a too 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
significant prolongation of the time before the first repair. If the user intentionally does not
follow the guidelines presented above, it will not cause the loss of any warranty rights or the
engine’s damage, but it is important to bear in mind that preserving the engine in the best
shape during further exploitation depends on how we handle it in the first hours.
The run-in time for the “OCTAGON 190” engine is about 15-20 hours of flight.
The practical way of estimating the length of run-in stage is using up 1 litre bottle of
oil.
2016-06-22
1
mixture is too lean
– it could damage
the engine,
2
mixture is too rich,
but is correct for
the run-in time
3
correct electrode
hue, optimal
mixture
4
new spark plug –
for comparison
