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1. 05:39 PM - Re: Re: Engine roughness Engine roughness (Hugh McKay)
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| Subject: | Re: Engine roughness Engine roughness |
OK guys, Thom, Ron, Rick, Roger, Dick, Clive and others:
I have found the problem and fixed it. I took all of your advice and
counsel and went back again and began to systematically check each wire
especially at or near the plug connectors on top of the engine. I went
back and re-checked all the wiring one more time. This time I found a
small break in the grey wire that goes into the A module coming from the
connector to the red power wire coming up from the engine. I
disconnected the plug and began to ohm the grey wire to ground. I got an
open circuit. When I closely examined the crimped end of the connector
on the end of the grey wire there were only a few strands of conductor
that were not broke. Most were broke. I noticed also that the ends of
the grey wires were not "tinned" before being crimped to the connector.
They were just stripped and the connector plug crimped on the strands.
This is very poor practice, and no wonder this type problem keeps
showing up on these engines.
Anyway, I cut the old connector completely off, "tinned" the bare ends
of the brown wire and and the red wire, crimped on a new insulated
male/female spade connector, secured everything and fired the engine up.
Every thing is now working normal. She is "purring like a kitten"!
Going flying tomorrow!!
Thanks,
Hugh McKay
From: Clive Richards
Sent: Sunday, August 22, 2010 5:00 PM
Subject: Re: RotaxEngines-List: Re: Engine roughness Engine roughness
Hugh
I have only looked a while ago at an engine we have on
the bench as plane is not built yet but think you will find the modals
are Identical and as they are connected by plugs & Sockets you can swap
them over. Our engine is an old one & has a different arrangement on the
plugs to the current ones so if you need spares you need to get the
correct one.
>From your test the left module is faulty as when you kill the right
module the engine stops
Swap the P leads plugs at module end & if fault swaps moduals then
switch or P lead is faulty.
You previously mentioned disturbing a trigger coil lead if this lead
has gone open circuit this will stop that module working as it fires 2
cylinders.
I presume all was working ok originally but have you disturbed the
plugs ?
I notice from the manual that 2 plugs are fired at the same time by the
ignition coils so a faulty open plug will stop the engine if that modual
only is selected.
do not archive
Clive
From: Hugh McKay
To: rotaxengines-list@matronics.com
Sent: Sunday, August 22, 2010 1:45 AM
Subject: Re: RotaxEngines-List: Re: Engine roughness Engine roughness
OK guys, We have checked all the wiring everyone has suggested for
continuity:
"P" leads, Kill Switches, wires to all the ignition pick-ups, and the
two red wires going down to the engine (these two red wires are grounded
in the engine per the Rotax 912 engine wiring diagram, so we just
disconnected one end of each red wire on top of the engine and ohmed
each wire to ground and we got continuity. Therefore we assume the red
wires are good. We put everything back together and the engine did the
exact same thing. The engine started and ran, but had a slight roughness
to it. I ran it up to 2200 rpm and killed the left mag switch. There was
no drop in rpm at 2200. The engine continued to run. I then opened the
left mag switch and closed the right mag switch, and the engine died
(was killed) immediately. Same problem!!
Dick you suggested switching all the wires from one ignition module to
the other. Are they identical and can they be switched without harming
the engine? If we do this and the problem still occurs, but is on the
other mag, what does this tell us? If the problem still occurs but is on
the same mag, what does that tell us?
Still searching,
Hugh McKay
Allegro 2000 ELSA
Rotax 912 UL
N661WW
From: Catz631@aol.com
Sent: Saturday, August 14, 2010 10:31 AM
To: rotaxengines-list@matronics.com
Subject: Re: RotaxEngines-List: Re: Engine roughnessEngine roughness
Hugh,
Something else you might try is switching wires from one module to
the other and see if the problem follows.
Dick Maddux
Milton Fl
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