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Rough runing above idle.

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Tucsonchris

Joined: 26 Oct 2007
Posts: 12
Location: Tucson, Arizona

Posted: Sun Oct 24, 2010 6:36 am Post subject: Rough runing above idle.

This problem appeared suddenly and really has me stumped.



I can't get the throttle above idle without severe roughness. If I add choke I can get it smoothly up to 2800 or so, but without the choke, I can't move my throttle above 2000 with out the engine running rough and quitting. It idles fine after warmup any where from 1600 -1800.



I had 1.5 smooth running hours before all this on my brand new 912S. I was preparing to do a pneumatic balance, so I started from scratch and redid my mechanical sync first. Then I redid it 5 more times to be sure my throttle levers were moving in unison. They are. They also reach their Hi speed stops at the same time.



Like I said, this is a brand new engine that ran great out of the box initially. My mag check even at idle had consistent, but not fatal, drops on both sides. EGT'S go up fast and hover around 1000. All other readings nominal. No gas coming from carb vent lines. Slides move easily.



This just isn't feeling like out of balance carbs--but I hope someone has some ideas. It reminds me of a distributor that won't advance on acceleration...



Tucson Chris

lucien

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

Posted: Sun Oct 24, 2010 6:55 am Post subject: Re: Rough runing above idle.

 	  Tucsonchris wrote: 	
		  This problem appeared suddenly and really has me stumped.



I can't get the throttle above idle without severe roughness. If I add choke I can get it smoothly up to 2800 or so, but without the choke, I can't move my throttle above 2000 with out the engine running rough and quitting. It idles fine after warmup any where from 1600 -1800.



I had 1.5 smooth running hours before all this on my brand new 912S. I was preparing to do a pneumatic balance, so I started from scratch and redid my mechanical sync first. Then I redid it 5 more times to be sure my throttle levers were moving in unison. They are. They also reach their Hi speed stops at the same time.



Like I said, this is a brand new engine that ran great out of the box initially. My mag check even at idle had consistent, but not fatal, drops on both sides. EGT'S go up fast and hover around 1000. All other readings nominal. No gas coming from carb vent lines. Slides move easily.



This just isn't feeling like out of balance carbs--but I hope someone has some ideas. It reminds me of a distributor that won't advance on acceleration...



Tucson Chris 	




Sounds like crapola in the carbs to me. What makes me think that is you say it came on suddenly and that engaging the chokes makes the engine go ahead and run up. So sounds more like fuel starvation rather than too much fuel.



If it's a new installation, I'd personally go through and redo your fuel lines too if you do discover it's debris in the carbs. Flush the entire thing, check for any lines/connectors not made properly etc..... 



BTDT and fortunately the problem showed itself on the t/o run before I managed to get in the air..... 



LS

_________________
LS
Titan II SS

b.carl@sympatico.ca

Joined: 20 May 2008
Posts: 77

Posted: Sun Oct 24, 2010 9:46 am Post subject: Rough runing above idle.

Chris

It looks like the slide in one of your carbs may not be opening or the main 

jet is clogged. Do a vacuum balance check to see which carb is the cause and 

trouble-shoot that carb.

Carl

912 ul

---

dan(at)azshowersolutions.
Guest

Posted: Sun Oct 24, 2010 3:55 pm Post subject: Rough runing above idle.

Chris,

We are all taking stabs at what could be the problem, so I will give you one 

more thing to look at...We have a couple of guys on another list that had this 

exact problem...new engine, about an hour on the thing, then wham...rough idle. 

It has boiled down to using ethanol fuel in fiberglass tanks. The tell-tale sign 

was a brown film (sticky stuff) that turns into a glaze of sorts inside the carb 

and everywhere thereafter.  Check the ventrui area of your carb for the brown 

sticky stuff. If you have fiberglass tanks...look inside them and see if the 

fuel has turned brown or tan. if it has, you will want to drain the tanks. The 

fix for these other guys was taking the carbs apart ASAP and cleaning them with 

carb cleaner... the longer you wait the harder it is to clean the stuff off. 

They then had to make a choice...change out the tanks with ones that are ethanol 

friendly or clean out the existing tanks very well and then slosh with Kreem 

(which is impervious to anything thrown at it).  



Best Wishes

Dan



---

Tucsonchris

Joined: 26 Oct 2007
Posts: 12
Location: Tucson, Arizona

Posted: Sun Oct 24, 2010 9:03 pm Post subject: Re: Rough runing above idle.

Problem solved--



My tanks were dissolving. These are the newest alcohol resistant tanks from Kitfox, BTW, so obviously nothing is truly alcohol resistant any more. My only solution is 100 LL--while it lasts. thanks for all the feedback.

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Sun Oct 24, 2010 9:47 pm Post subject: Re: Rough runing above idle.

http://www.wingtanks.com/



looks like same material the plastic gas cans are made of. 



My Kitfox is 1992 vintage and has plastic dash tank and  2 wings tanks of fiberglass.........  NO LEAKS YET !!  



I have over 1000 hours of ethanol gas usage on this plane alone.

Better look at  >  http://www.wingtanks.com/  I will buy these if mine ever start to leak.

_________________
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dirtfly7(at)yahoo.com
Guest

Posted: Mon Oct 25, 2010 7:03 am Post subject: Rough runing above idle.

Fiberglass tanks have to be coated with an ethanol resistant two part epoxy fuel tank coating system when they are built.  This has been working well and makes fiberglass tanks just as good as anything else.  Stay away from 100LL at all cost.

Joel



--- On Sun, 10/24/10, Tucsonchris <gallchrisa(at)qwest.net> wrote:

[quote]

From: Tucsonchris <gallchrisa(at)qwest.net>

Subject: Re: Rough runing above idle.

To: rotaxengines-list(at)matronics.com

Date: Sunday, October 24, 2010, 11:03 PM



--> RotaxEngines-List message posted by: "Tucsonchris" <[url=/mc/compose?to=gallchrisa(at)qwest.net]gallchrisa(at)qwest.net[/url]>



Problem  solved--



My tanks were dissolving. These are the newest alcohol resistant tanks from Kitfox, BTW, so obviously nothing is truly alcohol resistant any more. My only solution is 100 LL--while it lasts. thanks for all the feedback.





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=316931#316931

Navigator?RotaxEngines-List"  target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List  -->  [quote][b]

hgmckay

Joined: 23 May 2006
Posts: 397

Posted: Mon Oct 25, 2010 7:03 am Post subject: Rough runing above idle.

Tucsonchris,



I don't know much about the Kitfox airplane or the company, but if they 

would fabricate aluminum tanks, that would seem to solve the  problem.



Hugh McKay

Allegro 2000

Rotax 912 UL



--------------------------------------------------

From: "Tucsonchris" <gallchrisa(at)qwest.net>

Sent: Monday, October 25, 2010 1:03 AM

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

Subject: Re: Rough runing above idle.



 	  Quote: 	
		   

 <gallchrisa(at)qwest.net>



 Problem solved--



 My tanks were dissolving. These are the newest alcohol resistant tanks 

 from Kitfox, BTW, so obviously nothing is truly alcohol resistant any 

 more. My only solution is 100 LL--while it lasts. thanks for all the 

 feedback.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=316931#316931

kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Mon Oct 25, 2010 8:30 am Post subject: Rough runing above idle.

Would there be any reason to coat aluminum tanks?



On Mon, Oct 25, 2010 at 6:57 AM, Joel M. <dirtfly7(at)yahoo.com (dirtfly7(at)yahoo.com)> wrote:

 [quote]Fiberglass tanks have to be coated with an ethanol resistant two part epoxy fuel tank coating system when they are built.  This has been working well and makes fiberglass tanks just as good as anything else.  Stay away from 100LL at all cost.

 Joel



--- On Sun, 10/24/10, Tucsonchris <gallchrisa(at)qwest.net (gallchrisa(at)qwest.net)> wrote:

 	  Quote: 	
		   

From: Tucsonchris <gallchrisa(at)qwest.net (gallchrisa(at)qwest.net)>

Subject: Re: Rough runing above idle.

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

 Date: Sunday, October 24, 2010, 11:03 PM



--> RotaxEngines-List message posted by: "Tucsonchris" <gallchrisa(at)qwest.net>

 

Problem  solved--



My tanks were dissolving. These are the newest alcohol resistant tanks from Kitfox, BTW, so obviously nothing is truly alcohol resistant any more. My only solution is 100 LL--while it lasts. thanks for all the feedback.

 



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=316931#316931

Navigator?RotaxEngines-List"  target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List  --> 

 

	
  	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
[b]

pchristensen10(at)austin.
Guest

Posted: Mon Oct 25, 2010 8:45 am Post subject: Rough runing above idle.

Ethanol will corrode aluminum.

     

     Pete

     

     

     On 10/25/2010 11:27 AM, Ken Ryan wrote:     [quote]Would there be any reason to coat aluminum tanks?       

       

       

         

         On Mon, Oct 25, 2010 at 6:57 AM, Joel           M. <dirtfly7(at)yahoo.com (dirtfly7(at)yahoo.com)>           wrote:

            	  Quote: 	
		                                                                  Fiberglass                     tanks have to be coated with an ethanol resistant                     two part epoxy fuel tank coating system when they                     are built.  This has been working well and makes                     fiberglass tanks just as good as anything else.                      Stay away from 100LL at all cost.

                     Joel

                     

                     --- On Sun, 10/24/10, Tucsonchris <gallchrisa(at)qwest.net (gallchrisa(at)qwest.net)>                     wrote:

                      	  Quote: 	
		                         

                       From: Tucsonchris <gallchrisa(at)qwest.net (gallchrisa(at)qwest.net)>

                       Subject: Re: Rough runing above                       idle.

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

                       Date: Sunday, October 24, 2010, 11:03 PM

                       

                       --> RotaxEngines-List message posted by:                         "Tucsonchris" <gallchrisa(at)qwest.net>

                         

                         Problem solved--

                         

                         My tanks were dissolving. These are the newest                         alcohol resistant tanks from Kitfox, BTW, so                         obviously nothing is truly alcohol resistant any                         more. My only solution is 100 LL--while it                         lasts. thanks for all the feedback.

                         

                         

                         

                         

                         Read this topic online here:

                         

                         http://forums.matronics.com/viewtopic.php?p=316931#316931

                         Navigator?RotaxEngines-List" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List  -->                         

                           

                           

                         

                     	
                                                                              	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
           

	
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