Dave,
I had the same problem a few times with my 912S. What happened to mine was
a rite coming from the ignition module and going into the plug had broken.
It was right near the connector and in a tightly kinked area.
The pressure on the wire kept the broken ends pushed together so the problem
was intermittent - showed up as a very rough (very very rough) mag drop -
cutting out.
I found the problem after removing the ignition module. I solddered the
wire and all was well. It shoed again a few months later and the wire had
broken again closed to the plug so I removed the wire from the plug and
bypassed it with a butt connector - problem solved.
Those Ducati modules use some cheap wire, but the real problem is the way
they route it with very tight bends - my failures were also at the bends.
It was very difficult to trace - never could find it with a meter, because
of the broken wire being pushed together.
Thanks
Bob Jacobsen
N201WH
>From: "David DeFord" <davedeford@comcast.net>
>Reply-To: europa-list@matronics.com
>To: <europa-list@matronics.com>
>Subject: Europa-List: Ignition problem
>Date: Sun, 10 Oct 2004 21:28:08 -0700
>
>
>On my way to the Copperstate fly-in on Friday, I stopped in Bishop to pick
>up Kevin Klinefelter. We heard a loud, irregular popping noise in our
>headphones while taxiing to the runway, and the runup showed one rather
>rough mag. We checked the plugs and wires, finding no obvious problem with
>the wires, but the four plugs in the front cylinders were all very black,
>though they had only a few hours on them. (The rear plugs were all fine.)
>All plugs were replaced, and everything seemed smooth, including a standard
>runup. (During the troubleshooting, the engine had gone from very hot to
>very cool, with the cowls removed.) The popping noise began again on
>takeoff, so we returned to Bishop, and I dropped off Kevin. With poor
>weather in the forecast for the next day, I headed for home (180nm across
>the 13000-foot peaks of the Sierra). After a couple of episodes of very
>loud popping during the climb, everything quieted down again, so I
>continued
>on up to 15500 feet (912S/Airmaster power), crossed the mountains, and made
>it home without further incident.
>
>There are four ignition coils on the 912/914 engines, with each coil firing
>two cylinders (one live, one with valves open) at once. I measured the
>resistance between the pair of plug wires from each coil, and found 17K
>between the top plugs, and open circuits between the bottom plug pairs.
>The
>suspect coil (based on the rough mag and the black plugs in the front
>cylinders) is the forward coil on the port side, which fires the bottom
>front plugs. It is nearly impossible to see anything in the tangle of
>wires
>and hoses in this area, so I tried to remove the coil. After much
>struggle,
>I got most of the way to the coil, but determined that it would be
>necessary
>to either remove the engine from the ring mount, or remove the starboard
>side intake manifold to get the coil out. Access to many parts of the
>engine is difficult, but this is ridiculous.
>
>Each plug wire is sheathed in a rubber sleeve, which covers the "tower"
>where the wire enters the spark coil. Two of these sleeves are broken at
>the coil end. Does anyone know how to remove the spark plug connectors
>from
>the wires, or the wires from the coils? At least one of these must be
>necessary, in order to get the wires through the sleeves, and also through
>various other sleeves and holes. I suspect that the connectors may
>unscrew,
>but I'd hate to damage one by trying the wrong thing. The coils come with
>wires attached (at $280 each), but the wires and sleeves are also listed as
>separate parts. It seems likely that my problem is a wire that is sparking
>to the engine, or possibly sparking across a break in the coductor, but I
>can't figure out how to remove them for further testing or replacement.
>
>If anyone has experience troubleshooting or repairing the Rotax ignition
>coil assemblies, I'd certainly appreciate any advice.
>
>Dave DeFord
>N135TD
>
>
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