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Rough Running 912
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Goodone

Joined: 13 Sep 2008
Posts: 49

Posted: Thu Dec 04, 2008 12:49 pm Post subject: Rough Running 912

I have an 80 HP Rotax 912 UL that I like a lot. Lately I have noticed that there is a slight roughness in the engine if I cruise between about 4200 and 4600 rpm. I have not synchronized the carbs for over 2 years now because the engine seems to run fine at idle speeds less than 1800 rpm and I have been told that any unbalance between the carbs shows up at idle. I donâ€™t believe that there is any problem with the plugs. Any suggestions or constructive comments as to what the problem might be or as to how to trouble-shoot would be appreciated.

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Thu Dec 04, 2008 1:39 pm Post subject: Re: Rough Running 912

Hi Goodone,



You absolutely do have an unbalanced carbs. That's only because they haven't been balanced in so long. It should be done every 100 hr. or at least at the condition inspection each year if you have low time. Don't let anyone try to convince you otherwise and if someone has been to a Rotax school they absolutely wouldn't make a comment like that.

The rough running can absolutely be unbalanced carbs. One side of the engine is trying to run let's say at 4400 rpm and the other at 4500 rpm or worse. Think about what two opposing sides running at different rpm is doing to your engine and gear box over time. One of the most important things to do on your Rotax is to keep the carbs synced. It needs a mechanical and pneumatic sync. It is not hard and should be done asap. Whom ever told you an unbalanced carb sync only shows up at idle doesn't know what they are talking about. No matter what, the carbs will get out of balance over time. They will get out of balance for several reasons. (i.e. cable stretch, worn interior parts, leaks,ect...)

How many hours total on these carbs? They may even need a rebuild.

It's your hide and pocketbook at stake, so taking 30-60 min. to do a carb sync is cheap insurance.



If you need help please don't hesitate to call me. 520-574-1080

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Fri Dec 05, 2008 5:24 am Post subject: Rough Running 912

As usual Roger is right on the mark! You need to sync those carbs.I have had a similar problem and ended up replacing my throttle cables as one was slightly sticking on throttle reduction and one side of the engine was out from the other. This engine is basically two engines stuck together. The two sides have to be in sync. I bet I have synchronized my carbs at least 5-6 times in the last year.(for various reasons) Another thing they told us in Rotax school is to cruise the engine around 5000 rpm. The engine was designed to run at that rpm . I know my engine is much smoother when I do. Also idle no lower than 1800 rpm(Rotax school) as it is too hard on the gearbox (besides all the racket it makes)

                                                         Dick Maddux

                                                         Kitfox 4-1200

                                                         912UL

                                                         Pensacola,Fl



Stay in touch with ALL of your friends: update your AIM, Bebo, Facebook, andew-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000012">The NEW AOL.com.

  [quote][b]

Goodone

Joined: 13 Sep 2008
Posts: 49

Posted: Sat Dec 06, 2008 7:49 am Post subject: Re: Rough Running 912

Thanks for your input. I will sync the carbs ASAP.

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Dec 06, 2008 7:52 am Post subject: Re: Rough Running 912

Hi Goodone,



While doing the carbs you might want to check your prop blades for equal pitch. If you have an adjustable pitch prop check to make sure each blade is exactly the same pitch. This also causes vibrations.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Goodone

Joined: 13 Sep 2008
Posts: 49

Posted: Sun Dec 05, 2010 11:01 am Post subject: Re: Rough Running 912

Went flying this past Friday and the rough running 912UL was back in the mid range (4400-4800rpm) . Not real rough but noticeable to me. I have had this problem in the past (see beginning of this thread). Note that the rough running occurred at the same time of year in the past when the air here gets cold (40 F or below). The engine is in sync. Do you folks think a change in needle to richen the mixture a bit is the answer?

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sun Dec 05, 2010 11:17 am Post subject: Re: Rough Running 912

You said the engine is in sync? So you pneumatically synced the carbs? Mechanical doesn't really mean a lot. It is only a starting point. There are some people who do have a slight rough spot down around 4000-4400 when throttling back in the pattern. That may be normal, but it shouldn't be around the 4600 and above. What is your mag drop on each ignition and at what rpm are you doing the mag drop?

If it was a blade out from the others it will usually have a roughness throughout all rpms. What is your WOT rpm flat and level?



While were are at it, when you sync the carbs pneumatically that means they should be right on equal vacuum and not just close. If you can get them close them you can get them right on.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

joeing701(at)simnet.is
Guest

Posted: Sun Dec 05, 2010 11:26 pm Post subject: Rough Running 912

Hello Goodone.



This is exactly the same thing my friend has been experiencing on his Kitfox. His cure was to change the needle jet to the next larger size or from 2,72 to 2.80. Solved his problem but as Roger Lee has pointed out, this could just be a part of the problem, but the temps are normal in the mid range after the change.



Hope this helps,

Johann G.

Iceland.



----- Upprunalegt skeyti -----

FrÃ¡: "Goodone" <goodone41(at)verizon.net>

Til: rotaxengines-list(at)matronics.com

Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT +00:00 Monrovia

Efni: Re: Rough Running 912






Went flying this past Friday and the rough running 912UL was back in the mid range (4400-4800rpm) . Not real rough but noticeable to me. I have had this problem in the past (see beginning of this thread). Note that the rough running occurred at the same time of year in the past when the air here gets cold (40 F or below). The engine is in sync. Do you folks think a change in needle to richen the mixture a bit is the answer?





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=322365#322365

Goodone

Joined: 13 Sep 2008
Posts: 49

Posted: Mon Dec 06, 2010 6:38 am Post subject: Re: Rough Running 912

The carbs were synchronized pneumatically using the vacuum gage method. This was done several months back so it might have changed a bit but I don't think that this is the problem. I normally do my run-up at 3500 rpm and have a drops of about 100 rpm. Next time out I will take a look at the WOT rpm. However, I do think that the symptoms remind me of the lean carb problems that we have in the winter with our two-cycle engines. Raising the needle one notch would normally fix things with the two-cycle engine. I just didn't think the 912 would be as sensitive to this. The Lycoming and Continental engines normally don't show this sensitivity but I viewed one of the Rotex videos last night on adjusting the needles and this consideration was mentioned as a reason to change the needle position.

sdemeyer

Joined: 31 Jul 2009
Posts: 45

Posted: Mon Dec 06, 2010 7:23 am Post subject: Rough Running 912

I had this exact same problem as well. After spending months trying to fix, rebuilding carbs, replacing modules replacing wiring etc.... I finally gave up and took it to the Rotax dealer. He rebuilt the gearbox and the mid-range rough running problem went away! I would have never in a million years suspected the gearbox.



Scott

--- On Sun, 12/5/10, joeing701(at)simnet.is <joeing701(at)simnet.is> wrote:



 	  Quote: 	
		   From: joeing701(at)simnet.is <joeing701(at)simnet.is>

 Subject: Re: Re: Rough Running 912

 To: rotaxengines-list(at)matronics.com

 Date: Sunday, December 5, 2010, 11:21 PM

 --> RotaxEngines-List message

 posted by: "joeing701(at)simnet.is"

 <joeing701(at)simnet.is>

 

 Hello Goodone.

 

 This is exactly the same thing my friend has been

 experiencing on his Kitfox. His cure was to change the

 needle jet to the next larger size or from 2,72 to 2.80.

 Solved his problem but as Roger Lee has pointed out, this

 could just be a part of the problem, but the temps are

 normal in the mid range after the change.

 

 Hope this helps,

 Johann G.

 Iceland.

 

 ----- Upprunalegt skeyti -----

 Frá: "Goodone" <goodone41(at)verizon.net>

 Til: rotaxengines-list(at)matronics.com

 Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT +00:00

 Monrovia

 Efni: Re: Rough Running 912

 

 

 <goodone41(at)verizon.net>

 

 Went flying this past Friday and the rough running 912UL

 was back in the mid range (4400-4800rpm) . Not real rough

 but noticeable to me. I have had this problem in the past

 (see beginning of this thread). Note that the rough running

 occurred at the same time of year in the past when the air

 here gets cold (40 F or below). The engine is in sync. Do

 you folks think a change in needle to richen the mixture a

 bit is the answer?

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=322365#322365

 

 

 

 

 

 

 

 

 

 

 

 

 Lists This Month --

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 Raiser.  Click on

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 Dralle, List Admin.

 RotaxEngines-List Email Forum -

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lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Mon Dec 06, 2010 7:35 am Post subject: Re: Rough Running 912

 	  Goodone wrote: 	
		  The carbs were synchronized pneumatically using the vacuum gage method. This was done several months back so it might have changed a bit but I don't think that this is the problem. I normally do my run-up at 3500 rpm and have a drops of about 100 rpm. Next time out I will take a look at the WOT rpm. However, I do think that the symptoms remind me of the lean carb problems that we have in the winter with our two-cycle engines. Raising the needle one notch would normally fix things with the two-cycle engine. I just didn't think the 912 would be as sensitive to this. The Lycoming and Continental engines normally don't show this sensitivity but I viewed one of the Rotex videos last night on adjusting the needles and this consideration was mentioned as a reason to change the needle position. 	




Yeah it shouldn't be that hair-trigger on the 912. Even at those power settings you're starting to get into the high-speed mixture circuit which should be compensated for.  



It's a little harder to diagnose on a 4-stroke because it behaves pretty similarly when too rich or too lean. So it can be hard to tell which it is. 



The only installation-related thing I can think of to check is the carb vents (the overflows on the sides above the intakes); these need to be at the same atmopheric pressure as the air near the venturies. A common installation error is to just run the carb vents out into the breeze, i.e. stuff inbetween the carb bales. If you have the airbox or aircleaners, these lines need to be run inside them. Don't ask me how I know this and no it wasn't because I was just vigilant and read the installation manual .



So I'm also of the opinion that if you need to change the jetting, particularly at sea level, there may be another problem. Could be as simple as debris trapped in one (or even both) of the carbs. 



I live at 7000' MSL and kick around the patch at 10,000' MSL and my carbs only run slightly rich at the usual 2000-2500 rough spot with the factory jetting. I also have to lean out the idle mix. Otherwise, they're acceptable at 3500rpm and above....



LS

_________________
LS
Titan II SS

joeing701(at)simnet.is
Guest

Posted: Mon Dec 06, 2010 11:22 pm Post subject: Rough Running 912

Hi Scott.



When you had this engine rough running problem, did you notice any change or difference in the exhaust temp between cyl? 



Regards,

Johann G.

Iceland.

----- Upprunalegt skeyti -----

FrÃ¡: "Scott DeMeyer" <scottsr1100rt(at)yahoo.com>

Til: rotaxengines-list(at)matronics.com

Sent: MÃ¡nudagur, 6. desember, 2010 15:19:19 GMT +00:00 Monrovia

Efni: Re: Re: Rough Running 912






I had this exact same problem as well. After spending months trying to fix, rebuilding carbs, replacing modules replacing wiring etc.... I finally gave up and took it to the Rotax dealer. He rebuilt the gearbox and the mid-range rough running problem went away! I would have never in a million years suspected the gearbox.



Scott

--- On Sun, 12/5/10, joeing701(at)simnet.is <joeing701(at)simnet.is> wrote:



 	  Quote: 	
		   From: joeing701(at)simnet.is <joeing701(at)simnet.is>

 Subject: Re: Re: Rough Running 912

 To: rotaxengines-list(at)matronics.com

 Date: Sunday, December 5, 2010, 11:21 PM

 --> RotaxEngines-List message

 posted by: "joeing701(at)simnet.is"

 <joeing701(at)simnet.is>

 

 Hello Goodone.

 

 This is exactly the same thing my friend has been

 experiencing on his Kitfox. His cure was to change the

 needle jet to the next larger size or from 2,72 to 2.80.

 Solved his problem but as Roger Lee has pointed out, this

 could just be a part of the problem, but the temps are

 normal in the mid range after the change.

 

 Hope this helps,

 Johann G.

 Iceland.

 

 ----- Upprunalegt skeyti -----

 FrÃ¡: "Goodone" <goodone41(at)verizon.net>

 Til: rotaxengines-list(at)matronics.com

 Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT +00:00

 Monrovia

 Efni: Re: Rough Running 912

 

 

 <goodone41(at)verizon.net>

 

 Went flying this past Friday and the rough running 912UL

 was back in the mid range (4400-4800rpm) . Not real rough

 but noticeable to me. I have had this problem in the past

 (see beginning of this thread). Note that the rough running

 occurred at the same time of year in the past when the air

 here gets cold (40 F or below). The engine is in sync. Do

 you folks think a change in needle to richen the mixture a

 bit is the answer?

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=322365#322365

 

 

 

 

 

 

 

 

 

 

 

 

 Lists This Month --

 Some AWESOME FREE Gifts!)

 Raiser.Â  Click on

 out more about

 Gifts provided

 www.aeroelectric.com

 www.buildersbooks.com

 www.homebuilthelp.com

 Â  Â  Â  Â  Â  Â  Â  -Matt

 Dralle, List Admin.

 RotaxEngines-List Email Forum -

 FAQ,

 Â Â Â - MATRONICS WEB FORUMS -

sdemeyer

Joined: 31 Jul 2009
Posts: 45

Posted: Tue Dec 07, 2010 7:20 am Post subject: Rough Running 912

Johann, I only have EGT on one cylinder so I was not able to notice any difference. The vibration and rough running midrange was very frustrating. I thought the Rotax dealer was crazy when he told me the problem was more than likely the gearbox. I had replaced nearly every part in the fuel and electrical system and was fed up with the problem. Told him not to call me until the motor was fixed and ran smooth. I had about 400 hours on the motor. 



Scott



--- On Mon, 12/6/10, joeing701(at)simnet.is <joeing701(at)simnet.is> wrote:



 	  Quote: 	
		   From: joeing701(at)simnet.is <joeing701(at)simnet.is>

 Subject: Re: Re: Rough Running 912

 To: rotaxengines-list(at)matronics.com

 Date: Monday, December 6, 2010, 11:16 PM

 --> RotaxEngines-List message

 posted by: "joeing701(at)simnet.is"

 <joeing701(at)simnet.is>

 

 Hi Scott.

 

 When you had this engine rough running problem, did you

 notice any change or difference in the exhaust temp between

 cyl? 

 

 Regards,

 Johann G.

 Iceland.

 

 

 ----- Upprunalegt skeyti -----

 Frá: "Scott DeMeyer" <scottsr1100rt(at)yahoo.com>

 Til: rotaxengines-list(at)matronics.com

 Sent: Mánudagur, 6. desember, 2010 15:19:19 GMT +00:00

 Monrovia

 Efni: Re: Re: Rough Running 912

 

 

 <scottsr1100rt(at)yahoo.com>

 

 I had this exact same problem as well. After spending

 months trying to fix, rebuilding carbs, replacing modules

 replacing wiring etc.... I finally gave up and took it to

 the Rotax dealer. He rebuilt the gearbox and the mid-range

 rough running problem went away! I would have never in a

 million years suspected the gearbox.

 

 Scott

 

 

 --- On Sun, 12/5/10, joeing701(at)simnet.is

 <joeing701(at)simnet.is>

 wrote:

 

 > From: joeing701(at)simnet.is

 <joeing701(at)simnet.is>

 > Subject: Re: Re: Rough Running 912

 > To: rotaxengines-list(at)matronics.com

 > Date: Sunday, December 5, 2010, 11:21 PM

 > --> RotaxEngines-List message

 > posted by: "joeing701(at)simnet.is"

 > <joeing701(at)simnet.is>

 > 

 > Hello Goodone.

 > 

 > This is exactly the same thing my friend has been

 > experiencing on his Kitfox. His cure was to change

 the

 > needle jet to the next larger size or from 2,72 to

 2.80.

 > Solved his problem but as Roger Lee has pointed out,

 this

 > could just be a part of the problem, but the temps

 are

 > normal in the mid range after the change.

 > 

 > Hope this helps,

 > Johann G.

 > Iceland.

 > 

 > ----- Upprunalegt skeyti -----

 > Frá: "Goodone" <goodone41(at)verizon.net>

 > Til: rotaxengines-list(at)matronics.com

 > Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT

 +00:00

 > Monrovia

 > Efni: Re: Rough Running 912

 > 

 > 

 > <goodone41(at)verizon.net>

 > 

 > Went flying this past Friday and the rough running

 912UL

 > was back in the mid range (4400-4800rpm) . Not real

 rough

 > but noticeable to me. I have had this problem in the

 past

 > (see beginning of this thread). Note that the rough

 running

 > occurred at the same time of year in the past when the

 air

 > here gets cold (40 F or below). The engine is in sync.

 Do

 > you folks think a change in needle to richen the

 mixture a

 > bit is the answer?

 > 

 > 

 > 

 > 

 > Read this topic online here:

 > 

 > http://forums.matronics.com/viewtopic.php?p=322365#322365

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > Lists This Month --

 > Some AWESOME FREE Gifts!)

 > Raiser.  Click on

 > out more about

 > Gifts provided

 > www.aeroelectric.com

 > www.buildersbooks.com

 > www.homebuilthelp.com

 >               -Matt

 > Dralle, List Admin.

 > RotaxEngines-List Email Forum -

 > FAQ,

 >    - MATRONICS WEB FORUMS -

 > 

 > 

 > 

 > 

 

 

 

 

 

 

 

 Lists This Month --

 Some AWESOME FREE Gifts!)

 Raiser.  Click on

 out more about

 Gifts provided

 www.aeroelectric.com

 www.buildersbooks.com

 www.homebuilthelp.com

               -Matt

 Dralle, List Admin.

 RotaxEngines-List Email Forum -

 FAQ,

    - MATRONICS WEB FORUMS -

Goodone

Joined: 13 Sep 2008
Posts: 49

Posted: Tue Dec 07, 2010 12:36 pm Post subject: Re: Rough Running 912

I am not too sure about the gearbox being the problem in my case since this roughness only is noticeable in colder weather and goes away when it is warm. The roughness is very mild and probably not noticeable to a passenger in the aircraft. If we get some warm weather I will attempt to enrich the needle position and let you folks know how it works. I don't have access to a heated hanger so this might take awhile. 



Thanks for all your inputs. These ideas give me a number of things to consider.

moosepileit

Joined: 10 Dec 2007
Posts: 26
Location: USA

Posted: Tue Dec 14, 2010 9:50 am Post subject: Re: Rough Running 912

My Kitfox w/ 912 UL 80 hp came from a 5000' MSL field and is now hangared at sea level.  It was rough from around 4000 to 3700 rpm on a digital tach. and has 2 egts running (at) 1400 degrees.  



Carb needles were up at position 2.  Makes sense for where the plane used to live.  Dropped the clip to normal positions 3, raising the needle and the egts are the same, but now smooth running all rpms. (Thanks, Roger!)



I thought it might take dropping to clip position 4 to fully raise the needle or a change of needle and jet from standard as it's now mid 30's when I fly, but the position 3 did it for me.

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Tue Dec 14, 2010 10:26 am Post subject: Re: Rough Running 912

Position 3 on the carb needle is normal and a good place to be for the majority of us. If you live and fly from high elevations then maybe #2, but be ware if you come down to visit us low landers. 

#3 is good for most during summer and winter. The more you tinker against what Rotax advises the more chance of making a costly error or a poor running engine. You need to be able to fully understand the Rotax engine and how to accurately interpret engine information on the gauges or test equipment. If you don't then leave it as the factory set it up and you will fly to your TBO without any issues.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Tue Dec 14, 2010 3:54 pm Post subject: Rough Running 912

So all of this talk of changing needle positions based on altitude has me wondering. What if you want to fly from sea-level to high altitude? What then???



Ken Ryan

Anchorage, Alaska



 

On Tue, Dec 14, 2010 at 12:26 PM, Roger Lee <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)> wrote:

[quote] --> RotaxEngines-List message posted by: "Roger Lee" <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)>

 

 Position 3 on the carb needle is normal and a good place to be for the majority of us. If you live and fly from high elevations then maybe #2, but be ware if you come down to visit us low landers.

 #3 is good for most during summer and winter. The more you tinker against what Rotax advises the more chance of making a costly error or a poor running engine. You need to be able to fully understand the Rotax engine and how to accurately interpret engine information on the gauges or test equipment. If you don't then leave it as the factory set it up and you will fly to your TBO without any issues.

  

 --------

 Roger Lee

 Tucson, Az.

 Light Sport Repairman - Maintenance Rated

 Rotax Repair Center

 Home 520-574-1080  TRY HOME FIRST

 Cell 520-349-7056

 

 

 

 

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 http://forums.matronics.com/viewtopic.php?p=323365#323365

 

 

 

 

 

 

 

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lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Tue Dec 14, 2010 4:11 pm Post subject: Re: Rough Running 912

 	  kenryan wrote: 	
		  So all of this talk of changing needle positions based on altitude has me wondering. What if you want to fly from sea-level to high altitude? What then???



Ken Ryan

Anchorage, Alaska

	




You shouldn't have to change anything. I live at 7000' MSL (northern NM) and fly usually up to 9999' MSL, even on local messing-around flights. My carbs still have the factory jetting and they compensate fairly well. Mine run a bit rich at low power settings (i.e. between 2000 and 3000 or so on the ground or during approaches) and it's going to idle rich also (if you use the factory 1.5 turns on the idle needle). But at full power it still leans out fairly well, giving EGT's in the 1250 to 1350F range. 



So shouldn't be a problem...



LS

_________________
LS
Titan II SS

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Tue Dec 14, 2010 6:27 pm Post subject: Re: Rough Running 912

I'm with Lucien. leave it alone. You will be a little rich for that flight, but so what it will fly just fine. Making a permanent needle adjustment should mean you are more or less permanently at altitude.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Wed Dec 15, 2010 4:59 am Post subject: Rough Running 912

I could easily be taking off at sea level and then flying to over 14000.

Ken Ryan

Anchorage, Alaska

On Tue, Dec 14, 2010 at 6:11 PM, lucien <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)> wrote:

 [quote]--> RotaxEngines-List message posted by: "lucien" <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)>

 kenryan wrote:

 > So all of this talk of changing needle positions based on altitude has me wondering. What if you want to fly from sea-level to high altitude? What then???

 >

 > Ken Ryan

 > Anchorage, Alaska

 >

 You shouldn't have to change anything. I live at 7000' MSL (northern NM) and fly usually up to 9999' MSL, even on local messing-around flights. My carbs still have the factory jetting and they compensate fairly well. Mine run a bit rich at low power settings (i.e. between 2000 and 3000 or so on the ground or during approaches) and it's going to idle rich also (if you use the factory 1.5 turns on the idle needle). But at full power it still leans out fairly well, giving EGT's in the 1250 to 1350F range.

 So shouldn't be a problem...

 LS

 --------

 LS

 Titan II SS

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