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hgmckay
Joined: 23 May 2006
Posts: 397
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 Posted: Sat Sep 03, 2016 3:14 pm Post subject: Rough running 912 UL |
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Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. 704-661-8271
email hgmckay(at)bellsouth.net
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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dheal(at)sonic.net
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| Posted: Sat Sep 03, 2016 4:11 pm Post subject: Rough running 912 UL |
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Have you weighed your floats recently?
Sent via the Samsung Galaxy Alpha™, an AT&T 4G LTE smartphone
-------- Original message --------
From: Hugh McKay <hgmckay(at)bellsouth.net>
Date:09/03/2016 4:14 PM (GMT-08:00)
To: Rotax Engines <rotaxengines-list(at)matronics.com>
Subject: RotaxEngines-List: Rough running 912 UL
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. 704-661-8271
email hgmckay(at)bellsouth.net
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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hgmckay
Joined: 23 May 2006
Posts: 397
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| Posted: Sat Sep 03, 2016 4:15 pm Post subject: Rough running 912 UL |
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No, I havent.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: DHeal (dheal(at)sonic.net)
Sent: Saturday, September 03, 2016 8:10 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: RE: Rough running 912 UL
Have you weighed your floats recently?
Sent via the Samsung Galaxy Alpha™, an AT&T 4G LTE smartphone
-------- Original message --------
From: Hugh McKay <hgmckay(at)bellsouth.net>
Date:09/03/2016 4:14 PM (GMT-08:00)
To: Rotax Engines <rotaxengines-list(at)matronics.com>
Subject: Rough running 912 UL
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. 704-661-8271
email hgmckay(at)bellsouth.net
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Sat Sep 03, 2016 5:55 pm Post subject: Rough running 912 UL |
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Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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The smallest miracle right in front of you is enough to make you happy.... |
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vernon11
Joined: 03 Aug 2010
Posts: 14
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| Posted: Sun Sep 04, 2016 1:59 am Post subject: Rough running 912 UL |
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Have you had the carbs balanced? That is a sure sign. Also check the Idle jets. We had a lot of problems on a ULS with the idle jets.
Good luck,
Vernon.
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Sunday, September 4, 2016 1:14 AM
To: Rotax Engines (rotaxengines-list(at)matronics.com)
Subject: Rough running 912 UL
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. 704-661-8271
email hgmckay(at)bellsouth.net
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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wanastuffit(at)yahoo.com
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| Posted: Sun Sep 04, 2016 5:44 am Post subject: Rough running 912 UL |
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The fact that it happened so fast between one flight and another I would focus on electronic ignition. They will probably have to be replaced if they are the old type. $1,000.00
Sent from my iPad
On Sep 3, 2016, at 9:54 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:
| Quote: | Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Dee One
Joined: 29 Jun 2015
Posts: 48
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| Posted: Sun Sep 04, 2016 11:44 am Post subject: Rough running 912 UL |
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Yes, carbs have been dynamically balanced; new floats; new carb rebuilds; new plugs; new carb boots; etc. Since purchase, engine has run rough between 2200-2800 rpm’s. Do know why??
Regarding your rough running engine, it's my understanding that if you isolate the two carsb by pinching the balance line and the engine runs rough, this is an indication that the carbs are not balanced correctly. This is per the rotax-owner website.
Dee LeBlanc
leblancds(at)cox.net (leblancds(at)cox.net)
cell 225-802-1038
~~~~~~~~~~~~~~~~
The Past is History
The Future is a Mystery
Today is a Gift
That’s Why They Call it the Present
| Quote: | On Sep 4, 2016, at 4:55 AM, vernon mitchell <vernon11(at)xsinet.co.za (vernon11(at)xsinet.co.za)> wrote:
Have you had the carbs balanced? That is a sure sign. Also check the Idle jets. We had a lot of problems on a ULS with the idle jets.
Good luck,
Vernon.
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Sunday, September 4, 2016 1:14 AM
To: Rotax Engines (rotaxengines-list(at)matronics.com)
Subject: Rough running 912 UL
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037Allegro 2000
Rotax 912 UL780 hours TSN
Ph. 704-661-8271email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
_________________
The Past is History
The Future is a Mystery
Today is a Gift
That’s Why They Call it the Present |
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vernon11
Joined: 03 Aug 2010
Posts: 14
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| Posted: Mon Sep 05, 2016 2:43 am Post subject: Rough running 912 UL |
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Hugh.
As I said, I also had a big problem with the idle jets. On this occasion, although the jets looked clean after blowing through, there was what appeared to be a piece of fluff which could just be seen. Was about to put a gentle heat on it to burn it away, but managed to clear it. To this day, not a miss.
Good luck.
Vernon.
From: Dee LeBlanc (leblancds(at)cox.net)
Sent: Sunday, September 4, 2016 9:21 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Yes, carbs have been dynamically balanced; new floats; new carb rebuilds; new plugs; new carb boots; etc. Since purchase, engine has run rough between 2200-2800 rpm’s. Do know why??
Regarding your rough running engine, it's my understanding that if you isolate the two carsb by pinching the balance line and the engine runs rough, this is an indication that the carbs are not balanced correctly. This is per the rotax-owner website.
Dee LeBlanc
leblancds(at)cox.net (leblancds(at)cox.net)
cell 225-802-1038
~~~~~~~~~~~~~~~~
The Past is History
The Future is a Mystery
Today is a Gift
That’s Why They Call it the Present
| Quote: | On Sep 4, 2016, at 4:55 AM, vernon mitchell <vernon11(at)xsinet.co.za (vernon11(at)xsinet.co.za)> wrote:
Have you had the carbs balanced? That is a sure sign. Also check the Idle jets. We had a lot of problems on a ULS with the idle jets.
Good luck,
Vernon.
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Sunday, September 4, 2016 1:14 AM
To: Rotax Engines (rotaxengines-list(at)matronics.com)
Subject: Rough running 912 UL
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. 704-661-8271
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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hgmckay
Joined: 23 May 2006
Posts: 397
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| Posted: Mon Sep 05, 2016 11:18 am Post subject: Rough running 912 UL |
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Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the bad ones? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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hgmckay
Joined: 23 May 2006
Posts: 397
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| Posted: Wed Sep 07, 2016 4:28 pm Post subject: Rough running 912 UL |
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Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly skipping. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is killed the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I cant determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still dont know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the bad ones? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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John Hauck
Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)
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| Posted: Wed Sep 07, 2016 5:30 pm Post subject: Rough running 912 UL |
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For what it is worth.
Summer of 1994, I was flying my 80 hp 912 on a Kolb MKIII to Deadhorse/Prudhoe Bay, Alaska, for the first time from Alabama. Engine was nearly new with a flight to Sun and Fun prior to departing north. Soon as I got into Yukon Territory and cooler temps down in the 40s and 50s, I started having a rough running engine and loss of power. I made it to Deadhorse and back to Alabama without solving my problem. Soon as I got back to warm weather the problem disappeared. That winter I discovered the same problem. For some reason I pulled the enricher while flying in the mid-4000 rpm range. When I did, the rpm increased 200 rpm and the engine cleaned right up. When I pulled the enricher off the engine lost 200 rpm and ran rough. On the ground I raised the fuel needles one notch. That cured my problem.
As an added note. My spark plugs always looked like they were running rich, black and sooty, when in fact they were running just the opposite, very lean.
Something has to change to make a good running engine run badly. Usually, it is something obvious that we don't consider as a possible problem.
Since 1994, I have had two other engines on my MKIII, both 912ULS's. Never encountered the mixture problem with either of those engines which also pushed the MKIII to the Arctic Ocean and cold temps.
john h
mkIII
Titus, Alabama
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Hugh McKay
Sent: Wednesday, September 07, 2016 6:25 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rough running 912 UL
Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
-- “Blessed are the cracked, for they shall let in the light.†  Groucho Marx
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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ledson
Joined: 29 Apr 2009
Posts: 62
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| Posted: Wed Sep 07, 2016 5:46 pm Post subject: Rough running 912 UL |
|
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Hugh,
I assume that your carburetors have been rebuilt recently since your engine has 700+ hours on it. Rotax recommends that the Bing carbs be rebuilt every 200 hours. During my carb rebuild at 200 hours, a number of the seals and seats were found to be hard and worn. Once they were replaced I felt that my overall performance improved.
I wish you luck with figuring this out. Please keep us posted.
Larry Edson
N4362C
Sent from my iPad
On Sep 7, 2016, at 8:25 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.†  Groucho Marx
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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lcfitt3(at)gmail.com
Guest
|
| Posted: Wed Sep 07, 2016 5:55 pm Post subject: Rough running 912 UL |
|
|
Definitely not an expert in any sense, but I would check the module grounds. I would look to see if the grounds are run separately or are tied together as a common ground. If they are together, I would separate them in any event to give the true redundancy.
Lowell. 912 UL Kitfox IV,
On Sep 7, 2016 5:38 PM, "Hugh McKay" <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote: | Quote: | Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.†  Groucho Marx
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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BARRY CHECK 6
Joined: 15 Mar 2011
Posts: 738
|
| Posted: Wed Sep 07, 2016 6:21 pm Post subject: Rough running 912 UL |
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LOL...
You are as much an "Expert" as ROTAX!!
On Wed, Sep 7, 2016 at 9:49 PM, Lowell Fitt <lcfitt3(at)gmail.com (lcfitt3(at)gmail.com)> wrote:
| Quote: |
Definitely not an expert in any sense, but I would check the module grounds. I would look to see if the grounds are run separately or are tied together as a common ground. If they are together, I would separate them in any event to give the true redundancy.
Lowell. 912 UL Kitfox IV,
On Sep 7, 2016 5:38 PM, "Hugh McKay" <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote: | Quote: | Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.†  Groucho Marx
|
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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wanastuffit(at)yahoo.com
Guest
|
| Posted: Thu Sep 08, 2016 5:05 am Post subject: Rough running 912 UL |
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|
I had the same problem few years ago. After all that I did and frustration, the fix was overhaul my carbs. Lockwood did not find the smoking gun in the carbs but it diffidently fix it.
Sent from my iPad
On Sep 7, 2016, at 10:21 PM, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:
| Quote: | LOL...
You are as much an "Expert" as ROTAX!!
On Wed, Sep 7, 2016 at 9:49 PM, Lowell Fitt <lcfitt3(at)gmail.com (lcfitt3(at)gmail.com)> wrote:
| Quote: |
Definitely not an expert in any sense, but I would check the module grounds. I would look to see if the grounds are run separately or are tied together as a common ground. If they are together, I would separate them in any event to give the true redundancy.
Lowell. 912 UL Kitfox IV,
On Sep 7, 2016 5:38 PM, "Hugh McKay" <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote: | Quote: | Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.†  Groucho Marx
|
|
|
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
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vernon11
Joined: 03 Aug 2010
Posts: 14
|
| Posted: Thu Sep 08, 2016 7:03 am Post subject: Rough running 912 UL |
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|
Hugh.
With all that you have done, I am sure the last resort is the balance. With the miss on higher revs, that does cancel the idle jets.
Good luck, and keep us posted.
Regards,
Vernon.
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Thursday, September 8, 2016 2:25 AM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly skipping. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is killed the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I cant determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still dont know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the bad ones? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp” or “skip” a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
However, today when I started the engine it again was “skipping” at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Any suggestions as to what the problem may be?
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
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“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Thu Sep 08, 2016 1:26 pm Post subject: Rough running 912 UL |
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Hugh, Old mechanics proverb, "90% of carburetor problems are solved in the ignition system". That being said, have you checked the resistance of your spark plug wires? Since you'll have to re-seat the wires anyway, take the time to trim each end about 1/4" so that the screw connector has a chance to seat into fresh, un-corroded wire. Also check the screws themselves for signs of corrosion. Unless the wires are too short afterward this check won't cost you anything but your time. Almost all the information you need is available in the Heavy Maintenance Manual section 74-00-00.
Rick
Rick
On Wed, Sep 7, 2016 at 7:25 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Rick, Vernon, DHeal, Jeff, et al
I changed all eight plugs hoping that may take care of the rough engine operation but it had no effect. The engine behaved and ran the same as before changing the plugs. The engine starts fine, however after starting and closing the choke holding 2000 to 2200 rpm the engine is randomly “skipping”. Through out the operating range (2200 rpm to 4000 rpm) you can feel the engine missing randomly. With the engine operating at 4000 rpm, when one of the ignition switches is “killed” the engine suddenly looses about 1000 rpm and shakes violently. It does exactly the same thing when the other ignition switch is killed. So, the plugs are not the problem. From the behavior of the engine I can’t determine if the problem is in the ignition (electrical), or in the fuel/air mixture (carburetor). I did notice that the old plugs were black and sooty indicating a rich fuel mixture, but that was nothing new as I have always flown with that condition (i.e. the carbs have never been touched since new and have given me absolutely no problem in the 700+ hours that are on the engine since new).
Still don’t know where to focus my attention next to identify the problem. I guess my next step is to make sure the carbs are balanced. If they are, and the problem remains it must be electrical rather than a carb problem
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Hugh McKay (hgmckay(at)bellsouth.net)
Sent: Monday, September 05, 2016 3:17 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Rick,
The two Ducati ignition boxes have been on the engine since 2007. Engine and boxes were brand new then. How do I know if they were the “bad ones”? They have over 700 hours operation with out a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. [url=tel:704-661-8271]704-661-8271[/url]
Fax [url=tel:704-483-5466]704-483-5466[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
From: Richard Girard (aslsa.rng(at)gmail.com)
Sent: Saturday, September 03, 2016 9:54 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rough running 912 UL
Have you checked the ignition boxes to see if they are the known bad ones? Does the engine exhibit any trouble starting? Have you checked for a broken spark plug? When was the last time you trimmed and reseated the plug wires at each end (they screw on)?
Rick Girard
On Sat, Sep 3, 2016 at 6:14 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
| Quote: | Started to fly my Allegro 2000 (912 UL engine) today and suddenly my engine is running rough. On some earlier flights I noticed the engine wanting to “burp†or “skip†a little bit at idle and low rpms (2000 to 2500), however at higher rpms it seemed to smooth out. I had no symptoms while in flight.
Â
However, today when I started the engine it again was “skipping†at low rpms. Went through the check list and came to the point where I checked both ignitions at 4000 rpm. Ran the engine up to 4000 rpm and turned off one ignition. The engine suddenly ran very rough. When I checked the other ignition the same thing happened. To say the least I did not fly. took it back to the hanger and parked it.
Â
Any suggestions as to what the problem may be?
Â
Hugh G. McKay III
Denver, NC 28037
Allegro 2000
Rotax 912 UL
780 hours TSN
Â
Ph. [url=tel:704-661-8271]704-661-8271[/url]
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
|
--
“Blessed are the cracked, for they shall let in the light.†  Groucho Marx
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“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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John Hauck
Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)
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| Posted: Thu Sep 08, 2016 2:05 pm Post subject: Rough running 912 UL |
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Might be a good time to replace the connectors. Those have been rapid wear parts on my three 912s. They can be bought from Sparkplugs.com by getting the part number off of a connector. Price is a quarter what Rotax wants for them.
john h
mkIII
Burns Junction, Oregon
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Richard Girard
Sent: Thursday, September 08, 2016 3:25 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rough running 912 UL
Hugh, Old mechanics proverb, "90% of carburetor problems are solved in the ignition system". That being said, have you checked the resistance of your spark plug wires? Since you'll have to re-seat the wires anyway, take the time to trim each end about 1/4" so that the screw connector has a chance to seat into fresh, un-corroded wire. Also check the screws themselves for signs of corrosion. Unless the wires are too short afterward this check won't cost you anything but your time. Almost all the information you need is available in the Heavy Maintenance Manual section 74-00-00.
Rick
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John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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h&jeuropa
Joined: 07 Nov 2006
Posts: 645
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| Posted: Fri Sep 09, 2016 3:52 am Post subject: Re: Rough running 912 UL |
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Hugh,
Since you get the same result when you run on either ignition module, chances are the problem is not the ignition modules or other electrical issue.
Like the others, we suggest you get your carbs rebuilt. Not only do carbs need inspection every 200 hours, they contain rubber parts so they fall under the 5 year replacement requirement. Likely the o-rings are hard, the diaphragms are stiff and the needles are worn.
We went to the school at LEAF several years ago and after seeing how they totally strip them and replace all wear items, we decided it was a good investment to have someone who rebuilds carbs every day do ours rather than doing it ourselves. Ours have been rebuilt twice in 770 hours and we've been very happy with our decision. Each year at condition inspection, we check carb balance but no adjustment is necessary.
Jim & Heather
Europa XS, 914 770 hous
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hgmckay
Joined: 23 May 2006
Posts: 397
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| Posted: Sat Sep 10, 2016 1:08 pm Post subject: Rough running 912 UL |
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Gentlemen (bjones,jelling Catz631 h&, Jeff Wemmelring, Bick Girard, John Hauck, Lowell Fitt, Dee LeBlanc, GHeal, et al)
Well I found what was causing my rough running engine!! I am some what embarrassed, but it demonstrates how careful one must be when doing anything to a Rotax 912 series engine. All this started when I began to hear excessive engine noise in my head sets when transmitting on my radio. Well, if you read my earlier questions regarding the engine noise you will recall that I was advised (good advice)to first check all the grounds. This I did and found no bad grounds. In the course of checking the grounds there are two grounding points on the right side of the ignition modules where two screws screw down into the engine. One of these ground points has two ground wires attached to it. The other has three ground wires attached. I removed these grounds, cleaned them and reattached them to their proper screw location; or I thought I had. Well, after looking carefully at the top of the engine at these two ground points and feeling all of the wires in that area I found two loose black wires with a common ring terminal tucked under the intake manifold on that side of the engine. Well what a surprise!! Then I began to think, how can that be?? Then I noticed that these two wires with the common ring terminal exactly fit one of the two ground points I have just described. I then realized that I had pushed the end of this double ground wire with the common ring terminal under the manifold to get better access to clean the ground point. What I did not remember when it came time to reattach all the wires was that I had tucked this ground wire out of sight. I reattached all the visible ground wires forgetting I had tucked one out of sight.
Lesson learned! Make sure you know how many wires you have disconnected, and reconnect the same number. Anyway, I am back flying and the engine is running fine. Flew down to the big Triple Tree Fly-In just below Woodruff, SC today with out a problem except the noise in my radio which is another story. Many thanks for all of your suggestions. I value them and your willingness to share.
Regards,
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: John Hauck (jhauck(at)elmore.rr.com)
Sent: Thursday, September 08, 2016 6:05 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: RE: Rough running 912 UL
Might be a good time to replace the connectors. Those have been rapid wear parts on my three 912s. They can be bought from Sparkplugs.com by getting the part number off of a connector. Price is a quarter what Rotax wants for them.
john h
mkIII
Burns Junction, Oregon
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Richard Girard
Sent: Thursday, September 08, 2016 3:25 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rough running 912 UL
Hugh, Old mechanics proverb, "90% of carburetor problems are solved in the ignition system". That being said, have you checked the resistance of your spark plug wires? Since you'll have to re-seat the wires anyway, take the time to trim each end about 1/4" so that the screw connector has a chance to seat into fresh, un-corroded wire. Also check the screws themselves for signs of corrosion. Unless the wires are too short afterward this check won't cost you anything but your time. Almost all the information you need is available in the Heavy Maintenance Manual section 74-00-00.
Rick
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