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912s runs rough

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sldpileit(at)aol.com
Guest

Posted: Thu Oct 19, 2006 9:45 am Post subject: 912s runs rough

Ok guys and gals, I would love some help with this one. After 15 hrs of great flying my engine has dropped 300 rpm static. and feels like its missing on a climbing crosswind turn. Filters have been chg'd and also the spark plugs. I've had the carbs redone and tanked at rotax in Sebring Florida. I still have the same problem. the engine runs very smooth untill you get in that climbing crosswind turn. Very unnerving. I have also chg'd out the gas (from aviation to car) Still have the same problem. I can reduce the throttle to below 4500 rpm and missing goes away. I have tried to sneak up on the throt  tle in straight and level downwind, but the missing returns. I would love to hear from you guys on this one. The tech's at rotax are running out of ideas.

    

    

   MSGT SCOTT L. DINGMAN RRT,USAFR

 SLDPILEIT(at)AOL.COM

    

    [quote][b]

Gilles.Thesee(at)ac-greno
Guest

Posted: Thu Oct 19, 2006 10:00 am Post subject: 912s runs rough

sldpileit(at)aol.com a écrit :

 	  Quote: 	
		   Ok guys and gals, I would love some help with this one. After 15 hrs 

 of great flying my engine has dropped 300 rpm static. and feels like 

 its missing on a climbing crosswind turn. Filters have been chg'd 

 and also the spark plugs. I've had the carbs redone and tanked at 

 rotax in Sebring Florida. I still have the same problem. the engine 

 runs very smooth untill you get in that climbing crosswind turn. Very 

 unnerving. I have also chg'd out the gas (from aviation to car) Still 

 have the same problem. I can reduce the throttle to below 4500 rpm and 

 missing goes away. I have tried to sneak up on the throt tle in 

 straight and level downwind, but the missing returns. I would love to 

 hear from you guys on this one. The tech's at rotax are running out of 

 ideas.


	


Hi,



The fact that the problem goes away when you reduce throttle seems an 

indication of some (partial) fuel starvation. Does the engine shake and 

spit back ?



Have you made sure to rule out any airframe issue ?

Qty in tank(s)

Boost pump on or off ?

Air trapped in lines (I've seen some tortuous fuel line routing)

Kinked fuel line (some Europas seem  to have hose fuel lines between 

tank and firewall)

Location of pickup relative to tank in a climb

Swarf/dirt/water in tank

Blocked pick-up screen

Blocked tank vents

Etc...



BTW, what if you don't take that climbing turn, and continue straight on ?



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

riddon(at)sent.com
Guest

Posted: Thu Oct 19, 2006 10:56 am Post subject: 912s runs rough

I had a similar problem early in the engine’s life and it turned out to be a kink in one of the throttle cables inside the throttle box.  This put the carb’s out of synch as I throttled back but was not easy to find when the aircraft was on the ground.  

   

May not be this but it could be worth having a look.  

   

Richard Iddon. G-RIXS  

   

-----Original Message-----

 From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of sldpileit(at)aol.com

 Sent: 19 October 2006 18:44

 To: europa-list(at)matronics.com

 Subject: 912s runs rough  

     

Ok guys and gals, I would love some help with this one. After 15 hrs of great flying my engine has dropped 300 rpm static. and feels like its missing on a climbing crosswind turn. Filters have been chg'd and also the spark plugs. I've had the carbs redone and tanked at rotax in Sebring Florida. I still have the same problem. the engine runs very smooth untill you get in that climbing crosswind turn. Very unnerving. I have also chg'd out the gas (from aviation to car) Still have the same problem. I can reduce the throttle to below 4500 rpm and missing goes away. I have tried to sneak up on the throt tle in straight and level downwind, but the missing returns. I would love to hear from you guys on this one. The tech's at rotax are running out of ideas.  

    

   

    

   

    

MSGT SCOTT L. DINGMAN RRT,USAFR

 SLDPILEIT(at)AOL.COM  

        

  

   	  Quote: 	
		              - The Europa-List Email Forum -   --> http://www.matronics.com/Navigator?Europa-List              - NEW MATRONICS WEB FORUMS -   -->               - NEW MATRONICS LIST WIKI -   -->              - List Contribution Web Site -  Thank you for your generous support!                              -Matt Dralle, List Admin.   -->  	


     

  

--

 19/10/2006

  

  

--

 19/10/2006

     [quote][b]

topglock(at)cox.net
Guest

Posted: Thu Oct 19, 2006 11:34 am Post subject: 912s runs rough

Alan,



As Gilles shows, there could be several reasons for your problem.  More 

to consider.  If the condition only appears when the engine is under a 

load, consider the ignition module.  Sometimes, heat will cause them to 

break down, causing a simillar problem to the one you're experiencing.  

There's also the possibility of a small hole in the fuel line, before 

the fuel pump, causing air injestion.  And then there's good ol' vapor 

lock.  Check the orifice in your return line, for obstructions...



Rman - Baby Blue

123 hours



Gilles Thesee wrote:



 	  Quote: 	
		   

 <Gilles.Thesee(at)ac-grenoble.fr>



 sldpileit(at)aol.com a écrit :



> Ok guys and gals, I would love some help with this one. After 15 hrs 

> of great flying my engine has dropped 300 rpm static. and feels like 

> its missing on a climbing crosswind turn. Filters have been chg'd and 

> also the spark plugs. I've had the carbs redone and tanked at rotax 

> in Sebring Florida. I still have the same problem. the engine runs 

> very smooth untill you get in that climbing crosswind turn. Very 

> unnerving. I have also chg'd out the gas (from aviation to car) Still 

> have the same problem. I can reduce the throttle to below 4500 rpm 

> and missing goes away. I have tried to sneak up on the throt tle in 

> straight and level downwind, but the missing returns. I would love to 

> hear from you guys on this one. The tech's at rotax are running out 

> of ideas.

 Hi,



 The fact that the problem goes away when you reduce throttle seems an 

 indication of some (partial) fuel starvation. Does the engine shake 

 and spit back ?



 Have you made sure to rule out any airframe issue ?

 Qty in tank(s)

 Boost pump on or off ?

 Air trapped in lines (I've seen some tortuous fuel line routing)

 Kinked fuel line (some Europas seem  to have hose fuel lines between 

 tank and firewall)

 Location of pickup relative to tank in a climb

 Swarf/dirt/water in tank

 Blocked pick-up screen

 Blocked tank vents

 Etc...



 BTW, what if you don't take that climbing turn, and continue straight 

 on ?



 Regards,

 Gilles Thesee

 Grenoble, France

 http://contrails.free.fr

BEBERRY(at)aol.com
Guest

Posted: Thu Oct 19, 2006 12:29 pm Post subject: 912s runs rough

I had a similar problem when I found  (after a long time) that one of  the carb main jet needles had jumped out of its seating.  Worth a  thought?

  

 Patrick

  [quote][b]

BEBERRY(at)aol.com
Guest

Posted: Thu Oct 19, 2006 12:35 pm Post subject: 912s runs rough

After reading some of the replies to your pleas I am inclined to go along  with the throttle problem.  The cable , unless perfectly rigged can easily  kink when you want to apply more throttle.  Result- one carb goes out of  sync and engine runs 'rough'.

  

 One of the peculiarities of the Rotax is that you have to push the inner  cable through the outer, which is , basically , not a good idea as the cable is  not robust and has to be  - as per manual - looped in a particular fahsion  in order to avoid kinking or just plain 'sticking'

  

 Try this  - new cables if necessary or a re routing   initially.

  

 Patrick

  

  

  [quote][b]

Gilles.Thesee(at)ac-greno
Guest

Posted: Thu Oct 19, 2006 12:50 pm Post subject: 912s runs rough

Patrick,



 	  Quote: 	
		   After reading some of the replies to your pleas I am inclined to go 

 along with the throttle problem.  The cable , unless perfectly rigged 

 can easily kink when you want to apply more throttle.  Result- one 

 carb goes out of sync and engine runs 'rough'.


	


This is possible, but then, how does it agree with the "climbing turn" 

event ? But we know things happen in flight, flexing, buckling, binding...

 	  Quote: 	
		    

 One of the peculiarities of the Rotax is that you have to push the 

 inner cable through the outer, which is , basically , not a good idea 

 as the cable is not robust and has to be  - as per manual - looped in 

 a particular fahsion in order to avoid kinking or just plain 'sticking'

  


	


Why not dispense with the cables, and replace them with piano wires ? 

Your throttle linkage would turn into a push-pull system. Our airplane 

is rigged in this manner, with no problem whatsoever.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

BEBERRY(at)aol.com
Guest

Posted: Thu Oct 19, 2006 1:06 pm Post subject: 912s runs rough

Gilles, agree entirely with your views on throttle cables and  kinking.  Climbing turn?  Yes this would easily drop one loop of one  cable to one side and enhance an incipient chaffing problem on that  side.

  

 I think this has to be the answer.

  

 Patrick

  [quote][b]

SPurpura(at)aol.com
Guest

Posted: Thu Oct 19, 2006 4:52 pm Post subject: 912s runs rough

Have a look at your fuel filters,are there many bubbles? [quote][b]

william(at)wrmills.plus.c
Guest

Posted: Thu Oct 19, 2006 9:27 pm Post subject: 912s runs rough

Does the rough running go away when you  move the throttle lever back to full throttle?  That should test Richard's  suggestion.

 Regards,

 William

 [quote]   ---

rparigor(at)suffolk.lib.n
Guest

Posted: Thu Oct 19, 2006 10:02 pm Post subject: 912s runs rough

Hello Scott



"After 15 hrs of great flying my engine has dropped 300 rpm static. and

feels like its missing on a climbing crosswind turn."



Will throw some ideas out:



Check the rubber boots that connect carb to manifold for cracks



Make sure that the position of both carbs are synchronized



Install the new style float pivot pins as per bulletin



Check ignition pick up coil gaps and part numbers as per bulletin and

replace if called for in bulletin



Check your fuel tank vent to outside world



Check Muffler for cracks, leaks, and see if the baffles fell apart

internal



Make sure the fuel bowl vents are going to ambient pressure or air-cleaner

intake pressure and not restricting flow



Make sure you have proper heat range spark plugs, and proper gaps, and you

are using Whacker silicone based thermal conductive compound torqued as

per bulletin



Very important, make sure you do not have a restriction in fuel system,

kinked hose, or a nipple that has too small a ID (I was sent different

nipples, some had a very small ID that was pretty restricting) 



Still bent on restriction, do you have a factory fuel system? Not a Andair

Mini Gasculator in there by chance? If you do take it out and give a try.



Make sure restrictor for return flow not clogged, you did install a return

flow line?



If you try drinking through a straw with a pin hole in it, you know air is

a lot easier to suck up than the drink. Fuel system is no different, look

for leaks that are letting in air. Roger bull said he had sight T on

intake side of fuel system, and could get air sucking through the sight

when fuel was a bit low causing the plane to play Silent Night. a small

leak will cause your symptoms.



You have the proper size main jets? Are your jet needles set correct? Are

your carb diaphragms leaking> Do you have bulletin jet needle needle aux

hold downs installed?



Do you have any sort of special stuff in your fuel system that can be

skunking you? Like fuel flow transducer? Fuel pressure gauge sender that

is leaking in air?



Does it run same on both mags? is there excessive drop during mag check?



Did you try running off reserve? Does aux fuel pump help?



Is the routing of fuel lines insulated near hot under the cowl?



Check to see if you have any vacuum leaks, make sure cross tube hoses are

in good shape.



Give a try pitching nose up on ground and doing a static check? (I am just

shooting from hip, put on 3 car ramps, and pull tail way down and tie it

down??)



Is there a restriction between carbs and fresh air? Are the airfilters

restricting? Did you follow precise airfilter instructions?



Again fuel restriction, when your aeroplane is on car ramps with tail low,

run a fuel flow test in that configuration, do it for a while, like 10

gallons worth.



Check your ignition wiring:

http://www.greenskyadventures.com/engineservice/TechTips/912Ignition/912IgnDiagrahm.htm



Good luck



Ron Parigoris

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