>>The engine is furnished with an automatic ignition adjustment
controlled by
the edge of trigger cams on the flywheel and the electronic modules.
*NOTE: For easy engine start the ignition timing at start is 4d
B.T.D.C.
As soon as the engine runs the ignition timing will change over
automatically
to operation timing of
26d BTDC on ignition circuit A and
22d BTEC on ignition circuit B
The transition from start ignition timing to the timing for operation
takes place
between 650 to 1000 rpm.<<
Hi Bob
Thanks for this Rotax 914 ignition info. I was not supplied with a CD with
my 912S but have a copy of the 912 manual. This quotes 6deg BTDC for start
changing to 26 deg BTDC between 600 & 900rpm for both systems after start. I
suspect the 912S with its different compression ratio and capacity will be
different again. Does anyone have a copy of the 912S manual (paper or CD) so
that we can check this?
Using a single system is likely to produce a slower and less complete
ignition (hence the rpm drop on the mag check) so maybe this is the reason
why it seems to help. If the temporary delayed ignition reverts too quickly
during start this could cause the problem. If the 912S has different
settings for A and B systems (like the 914) maybe it would be better to use
B for start. With different ignition settings for each system one might
expect slightly differing sizes of mag drop between the two systems.
I will pass our discussion on to Nigel Beale (UK Rotax expert) to see if he
has any comments on this.
Regards
Nigel Charles
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