Salut Jean Philippe,
Je repond en anglais pour que tous en profitent. C=E2=80=99est mieux,
n=E2=80=99est
il pas ?
The infamous kick back happens when the first cylinder to ignite does so before
reaching top dead center (TDC =3D PMH in french) which is not unlikely with the
spark advance set, by design, at 4 degrees before TDC, and not adjustable.
Because the prop is driven through the slip clutch, there is no flywheel effect
and the crankshaft stops immediately. Then the prop uses its own inertia to
turn up to 30 degrees (slip clutch backlash) and violently hurts the dog. It is
so violent that it can damage your exhaust, carburettor flanges and engine
mount altogether, and possibly the engine itself. This happens mainly with the
bigger displacement and higher compression 912S, but I experienced it once or
twice with the 914 too. Rotax allegedly solved the issue with a more powerful
starter motor, but clearly the problem is still there with the new starter
motor.
Remi Guerner
F-PGKL, XS S/N395 monowheel, 288 hours on a 914 + 91 hours since fitted with
the 912S.
From: NEEL Jean Philippe <jeanphilippeneel@yahoo.fr>
Subject: RE: Europa-List: Kick back is back
Salut Remi
S'agit il de battements generants des vibrations importantes empechant le
demarrage?
JP Neel F-PSLH 650h
Rmi Guerner <air.guerner@wanadoo.fr> a crit :
In spite of having the heavy duty starter, a 6 months old 28 Amp-hour battery,
an ignition switch wired so that only one channel is energized during starting,
pulling the choke only after a few prop turns, I experienced the infamous kick
back again last week, during a few degrees above freezing cold start.
To help solving this problem, I am thinking at replacing the low cost battery by
a high performance one such as the Odyssey or Genesis. Any suggestion on where
to find this sort of batteries in Europe ?
Remi Guerner
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