Rotax Running Rough at 95F - Jul 2003

I had a problem on take-off with my Rotax 912 engine running rough. The
air temperature was 95F, but all engine temperatures were within
operating range. I aborted take-off and ran it up several times with no
problem.

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Date:         Wed, 2 Jul 2003 10:21:21 -0600
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         William Cotton <cotton@ATMOS.COLOSTATE.EDU>
Subject:      Rotax running rough at 95F
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I had a problem on take-off with my Rotax 912 engine running rough. The
air temperature was 95F, but all engine temperatures were within
operating range. I aborted take-off and ran it up several times with no
problem. Attempted another takeoff and after liftoff it briefly ran
rough again but cleared and then I climbed out and flew for 2hrs.  The
climb out was not impressive to say the least as the airfield is at
5000' at Fort Collins, CO so the density altitude was 8400'. I
attributed the poor climb to having two passengers and half load of fuel
as it seemed to be pulling 5200RPM. But I can't be certain that I wasn't
getting full power. When I went in pattern and lowered RPM to 4000 it
ran rough again but it again cleared out.

 I talked to the mechanic at FNL who has worked on a number of
uncertified 912's and he said that it is common for the engine to run
rich at those temp's and foul the plugs. Has anyone else experienced
such a problem? If so, other than cleaning or replacing plugs is there
anything else that can be done?

Bill Cotton
=========================================================================
Date:         Wed, 2 Jul 2003 16:40:26 -0500
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Horst Stratmann <horst.stratmann@UPCGROUP.COM>
Subject:      Re: Rotax running rough at 95F
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Hi Bill,

I once had a crack in the rubber flange which connects to carburetor to
the engine and the engine was running rough and finally did not start at
all. There was also a service bulletin from Rotax out and they had
changed the design of these flanges. You might want to give them another
good look again. Good luck.

Best regards

Horst Stratmann
S/N 200-096

-----Original Message-----
From: Ximango Owners Group [mailto:XIMANGO@HOME.EASE.LSOFT.COM] On
Behalf Of William Cotton
Sent: Wednesday, July 02, 2003 11:21 AM
To: XIMANGO@HOME.EASE.LSOFT.COM
Subject: Rotax running rough at 95F


I had a problem on take-off with my Rotax 912 engine running rough. The
air temperature was 95F, but all engine temperatures were within
operating range. I aborted take-off and ran it up several times with no
problem. Attempted another takeoff and after liftoff it briefly ran
rough again but cleared and then I climbed out and flew for 2hrs.  The
climb out was not impressive to say the least as the airfield is at
5000' at Fort Collins, CO so the density altitude was 8400'. I
attributed the poor climb to having two passengers and half load of fuel
as it seemed to be pulling 5200RPM. But I can't be certain that I wasn't
getting full power. When I went in pattern and lowered RPM to 4000 it
ran rough again but it again cleared out.

 I talked to the mechanic at FNL who has worked on a number of
uncertified 912's and he said that it is common for the engine to run
rich at those temp's and foul the plugs. Has anyone else experienced
such a problem? If so, other than cleaning or replacing plugs is there
anything else that can be done?

Bill Cotton