HIGH EGT & WON'T SHUT DOWN
in General Tech Discussion
13 years ago
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Re: HIGH EGT & WON'T SHUT DOWN
by Roger Lee » 13 years ago
Hi Bob,
Reduce the idle to 1700 and let it cool for 1-2 min. Turn one mag off for 3-4 seconds and then the next. Before shutdown. The EGT's should be lower once you move the EGT'S probes.
Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell
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Re: HIGH EGT & WON'T SHUT DOWN
by MARK JACKSON » 13 years ago
Hi Bob
Obviously Roger is right in what he says, but when you switch the mags off it should stop, no questions. If it was idling high then you may get a bit of kickback, but that's it.
I would also look at the module wires on this one as well. The older engines with the 4pin plugs had problems with the wires breaking down inside the PVC sheath, so the wire looked ok but you could get an intermittent connection. One of the main problems with the broken wire was sometimes when you switched the mags off, the engine kept running. If this is intermittent on one mag, it will cough and splutter as the vibration makes and then breaks the earthing connection.
I would suggest you pull all the wires on the modules. If the core is broken, the wire will stretch.
Good luck. Mark
IMG_1372.JPG (You do not have access to download this file.)
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Re: HIGH EGT & WON'T SHUT DOWN
by Roger Lee » 13 years ago
Mark is absolutely correct. Anytime you are checking wires then it should be from beginning to the end. Wires may have something laying on them and vibration wears through the insulation, wires break and hang on by a thread making a poor connection where the wire is crimped into the electrical connector and connections get corroded it its contact point and may still have a connection, but a poor one. Screws loosen, connectors work themselves apart, ect... So when looking at a wire look at all of it from beginning to end.
Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell
Thank you said by: Jan Nademlejnsky
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Re: HIGH EGT & WON'T SHUT DOWN
by Bob Turner » 13 years ago
Mark/Roger; Thanks for the input (Mark I appreciate the photo as well, that helps). The next time I get to the airport I'll check the wires closer and see if any may have a break internally. In addition I'll reduce the idle RPM and follow the recommended shutdown and we'll see what happens.
It is an older module and I can see the possibility of a break internally in the wires.
Thanks guys, I'll give you some feedback soon.
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Re: HIGH EGT & WON'T SHUT DOWN
by Bob Turner » 13 years ago
Mark/Roger; Sorry it has taken so long to get back. Mark, I did check all of the wiring and it was good. The wire to the ignition modules was not shielded, but I'm not getting any static so I'll change it in the future.
Roger, I finally got the EGT probes relocated and the old holes welded (I even found a small crack in the muffler and got it fixed at the same time).
At 5490 RPM I'm getting EGTs of 1527 and 1518 so the relocation of the probes had a definite impact, though not as much as I had hoped.
I have reduced the idle RPM so I can pull it down to 1600 just prior to shutdown. That seems to work well with no kicking back over (I do cool it first as recommended, shut down one mag and then pull it to idle (about 1600) and it shuts right down.
Things appear to be running smoothly at the moment and I really appreciate the input.
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