Hello all,
In order to sort out the kick back problem I experienced with my 912S, I checked
the trigger coils gap, as suggested by Andy in Factory Tech Talk. Surprisingly
none of them were found to be within the tolerances specified by ROTAX. The
specified gaps are between 0,3 and 0,4 millimeters. I measured gaps between
0.15 and 0.25 millimeters. I also found that the trigger coil B =C2=BE was
pushed
down by the alternator/ignition wiring harness, and therefore it was impossible
to adust the gap properly. The fix was to use a ty-wrap attached to
the engine mount ring so that the wiring harness is moved up out of the way.
I adjusted the gaps at around 0,4 mm and now the engine is starting a lot more
smoothly, with no kick back. It is obvious that the engine was delivered to
me with this wrong gap adjustment. Adusting these gaps is a time consuming
work,
as you have to remove a lot of stuff to get access to the back of the engine.
Therefore I strongly recommend that new builders check their trigger coils
before they hang the engine on the aircraft.
Remi Guerner
F-PGKL, XS S/N395 monowheel, 912S, 383 hours, installing an Airmaster prop
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