>Two cylinders have a big EGT rise when on single mag - can't be traced to
any
component other than the plugs and wires - Plug #3 A circuit and #4 B
circuit.<
This sounds a little strange. When the mag drop is excessive you would
expect to find a cylinder with low rather than high EGT. I fitted 4 EGT
senders so that I could identify the rogue cylinder in the event of a failed
mag drop check. The only thing I can think of is that the rise indicates
that those cylinders are OK and working harder to overcome poor ignition in
one or both the other cylinders.
Is the mag drop as bad when the engine is not fully warmed up and without
the top cowl on? If so I would suggest that it is unlikely to be caused by
overheated electronics..
Your problem doesn't sound a typical Rotax problem. As for Lycomings, in the
past I have known of two cases which had difficult to solve mag drop
problems so they are not exempt.
Nigel Charles
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