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High Egt's

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DAquaNut(at)aol.com
Guest

Posted: Fri Dec 14, 2007 4:02 pm Post subject: High Egt's

Gang,

  

      My 447 Firefly Has always been plagued by EGT's at  or over 1200* between 4000 rpm and 5400 rpm. If I put in more pitch, that cools  EGT's a bit but causes CHT's to increase.  

   CHT's are already as high as 400* at times so adding more  pitch is not the answer. I have the prop pitched for 6250 static.    The  EGT  temps are higher now that I am flying in  50* weather.  My main jet is 165 , needle jet.270, jet needle 15k2, with  clip in the lowest position. I have searched the archives all afternoon and have  not found a solution. It seems that going to a .272 needle would help.

    Anyone have a similar problem and solve it ?

  

                     Ed   ( Firefly 062) 



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Fri Dec 14, 2007 5:06 pm Post subject: High Egt's

Yep, I had the same problem with mine. I had to change the main jet needle  from the stock one- 15k2 to the next size which is 15E5U to get the mid range  right. Cost is about $7 bucks art CPS. It was controllable after I replaced the  stock one.

 Larry C  

 [quote]   ---

_________________
do not archive

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Fri Dec 14, 2007 5:53 pm Post subject: High Egt's

At 06:58 PM 12/14/2007, you wrote:

  	  Quote: 	
		   

      Gang,

  

      My 447 Firefly Has always been plagued by EGT's at or over 1200* between 4000 rpm and 5400 rpm. If I put in more pitch, that cools EGT's a bit but causes CHT's to increase.  

   CHT's are already as high as 400* at times so adding more pitch is not the answer. I have the prop pitched for 6250 static.   The  EGT  temps are higher now that I am flying in 50* weather.  My main jet is 165 , needle jet.270, jet needle 15k2, with clip in the lowest position. I have searched the archives all afternoon and have not found a solution. It seems that going to a .272 needle would help.

    Anyone have a similar problem and solve it ?

 	


 The "old manual" on the 447 said that the correct EGT cruising temp was 1200 - that meant it was not too rich

 (using too much gas) and not to lean (would hurt the engine). I you want to check it at 1200, pull the enricher (choke)

 if you have one and see if it doesn't drop your RPMs. I know it's not the same on a 503. I think you could even find

 it on "Airwolf's" old web site.

 That's just my recollection - I had one for 6 or 7 years and that's what I would run on trips.    [quote][b]

_________________
Possum

beauford173(at)verizon.ne
Guest

Posted: Fri Dec 14, 2007 6:11 pm Post subject: High Egt's

Brother Diebel...

  

 Welcome to the wonderful world of Adolf's revenge....diabolical  little 447's....   After five or six years of torment with my  own fiendish little demon from Gunskirchen, it is finally beginning to show  some intermittent indications of near normal thermal behavior...  I am  working under the assumption that this development is a subtle  indication that it is setting me up for the kill in the not too distant  future...

  

 Mine always ran a bit hot on the heads the first 100 hours or so; 360 on  them, the 1100  cruise EGT didn't bother me and it never got hotter than  that.   Following the great Rotax-Bing carbon darkness in the winter  of '05, you may recall that I ended up with new green-dot pistons and rings  installed by the the men with the black hoods within Castle  Lockwood... 

  

 Those pistons were too tight, I believe...and the head temps reflected that  condition.  I consistently had 400 to 415 on the heads during climbout and  they would run constant 390 plus at 5800 cruise...but meanwhile, I  kept the prop loaded enough to maintain cruise EGTs in the 1100 range, although  it would still always turn about 6200  or so static..   Have  about 60 hours on the green dots now and the hours have mellowed them somewhat  -- Overall, I now have my engine configured exactly as you describe  yours...   same jets, same metering rod, same notch, same static RPM  (6250 now), but gradually over the last 20 hours of operation,   I now see temps in the 340/1100 range at cruise.

  

 I am assuming that you have reliable instrumentation... (EIS..or equiv.  accuracy?)  and that you have checked the obvious things with the fan belt  tension, head bolt torque, intake manifold torque, possible cooling shroud  obstruction, etc. 

  

 What do your plugs show...?  gray or brown... light or dark...?   A lean mixture will definitely make 'em run head-hot. Induction vacuum  leaks and crank seal leaks can lean 'em right out...  Your jets-settings  are SOP -- If plugs are light gray with the jets and settings you are running,  I'd sure go leak hunting...  Stuck rings will prevent heat transfer to  the cylinder walls and also run up the head temps... What gasoline do you  run?

  

 I suspect five things have probably combined in mine to finally moderate  the temps:

     -- Pistons wore in and the tolerances eased  somewhat

     -- I switched from my normal fly-spray gasoline to   100% Amaco Supreme (noticed immediate positive impact on head temps).

     --Ambient air temps here dropped 20 degrees F... 95 to  75... (eat yer heart out up there, boys...hell, we're actually wearing  sweaters to fly now)

     --I had an epiphany about the impact of the idle air  adjustment screw on the Bing upon cruise CHT and choked that sucker down  to

 a little less than three-quarters of a turn...(also had a  perceptible temp impact)

     -- The Gunskirchen pre-kill protocol has likely been set  in motion... 

  

 Ed, I seem to offer free advice like I know what Rotax 447's are all  about.... I assure you that any human who has watched me chant, burn incense,  and dance around my 447 under a full moon wearing only a light coat of oil  and an Arturo Fuente will tell you that I ought to be the last person  on the planet offering advice...and I agree.

  

 What I do know is that something wonderful (read normal) has finally  happened to mine and the above factors...well the first four... are the  only

 things I can call to mind that I have changed, or suspect to have  changed with the engine.

  

 Prior to the improvement, was considering starting a separate 447  owners list and suicide watch support group...     now that the  pain has eased a trifle, may just sit around, drink Beefeaters, listen to the  formidible Mrs. Beauford and shove short bits of safety wire up under my  fingernails... and wait.

  

 Good luck with yours, Brother...

  

 Worth what ye paid fer it.

  

 Do Not Archive

  

 beauford

 FF-076 - N173BW

 Brandon, FL

 [quote]   ---

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Fri Dec 14, 2007 6:13 pm Post subject: High Egt's

 	  Quote: 	
		    	  Quote: 	
		  My main jet is 165 , needle jet.270, jet needle 15k2, with clip in the lowest position. I have searched the archives all afternoon and have not found a solution. It seems that going to a .272 needle would help.

    Anyone have a similar problem and solve it ? 	


 The "old manual" on the 447 said that the correct EGT cruising temp was 1200 - that meant it was not too rich

 (using too much gas) and not to lean (would hurt the engine). I you want to check it at 1200, pull the enricher (choke)

 if you have one and see if it doesn't drop your RPMs. I know it's not the same on a 503. I think you could even find

 it on "Airwolf's" old web site.

 That's just my recollection - I had one for 6 or 7 years and that's what I would run on trips. 	


 Here it is:

  http://www.800-airwolf.com/pdffiles/ARTICLES/part12.pdf



 The old finicky single carb 447 is not tuned the same as a dual carb CDI 503.

 At cruise speed  "5800 RPM" -  I think 1200 is fine. It should drop as you back off the throttle.    [quote][b]

_________________
Possum

DAquaNut(at)AOL.COM
Guest

Posted: Fri Dec 14, 2007 10:35 pm Post subject: High Egt's

Bill,

  

    I always run Exxon  mid or low octane with 10%  alcohol.  I can't get gas without alcohol here.   The last time I  looked at the plugs they were a light brown color.  Maybe It would run  cooler with higher octane????      At 5800 rpms it runs  about 1100 EGT. Its only around 4100----      5400 rpms  it goes over 1200. Was not as bad till temps got in the 50's here.  I may  try a different needle as the problem seems to be in the midrange.

  

  

                   Fly safe,

  

                   Ed Diebel 



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

DAquaNut(at)aol.com
Guest

Posted: Fri Dec 14, 2007 10:38 pm Post subject: High Egt's

In a message dated 12/14/2007 7:07:03 P.M. Central Standard Time,  lcottrell(at)fmtcblue.com writes:

  	  Quote: 	
		     Yep, I had the same problem with mine. I had to change the main jet    needle from the stock one- 15k2 to the next size which is 15E5U to get the mid    range right. Cost is about $7 bucks art CPS. It was controllable after I    replaced the stock one.

   Larry 

	


 

          Larry.

  

      I am going to get  a new needle ASAP and give  "R a try.

  

               Thanks.

  

                  Ed



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

DBforfun

Joined: 17 May 2007
Posts: 12
Location: N Calif.

Posted: Sat Dec 15, 2007 9:35 am Post subject: High Egt's

Put in a larger Main jet. This will bring your temps down.

  

 Order a Parts Catalog from California Power Systems. They are a Rotax  authorized dealer and in their catalog there is a very big section devoted to  the "Care and Feeding of Rotax engines". The articles in this section are  excellent for trouble shooting and fixing most problems with Rotax engines. They  are very well written and are in plain English that almost anyone can  understand. 

  

 http://www.800-airwolf.com/

  

 Good luck.

  

  

  

 In a message dated 12/14/2007 4:03:05 P.M. Pacific Standard Time,  DAquaNut(at)aol.com writes:

  	  Quote: 	
		     Gang,

    

        My 447 Firefly Has always been plagued by EGT's    at or over 1200* between 4000 rpm and 5400 rpm. If I put in more pitch, that    cools EGT's a bit but causes CHT's to increase.  

     CHT's are already as high as 400* at times so adding    more pitch is not the answer. I have the prop pitched for 6250 static.      The  EGT  temps are higher now that I am flying in    50* weather.  My main jet is 165 , needle jet.270, jet needle 15k2, with    clip in the lowest position. I have searched the archives all afternoon and    have not found a solution. It seems that going to a .272 needle would    help.

      Anyone have a similar problem and solve it ?

    

                         Ed   ( Firefly  062) 

	


 

  



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Dec 15, 2007 10:34 am Post subject: High Egt's

DBforfun:

  

 Won't that down EGT across the board?

  

 Ed D said his EGT is 1100 at 5800, but high in midrange  rpm.  

  

 I would think changing needle position or needle or needle jet  size would influence change in midrange.

  

 john h

 mkIII - A bit rusty on 2 cycle tuning.  Flying 4 strokes  since 1994.

  

  

 [quote]    



      Put in a larger Main jet. This will bring your temps down.

    

    



[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

DBforfun

Joined: 17 May 2007
Posts: 12
Location: N Calif.

Posted: Sat Dec 15, 2007 11:43 am Post subject: High Egt's

My thought would be to increase the main jet and then lower the  needle.

  

 Why not buy the adjustable main jet kit for the carb. This allows you to  adjust the carb. anytime as the weather changes or if you have the remote  adjustment you can readjust the carb. ( lean the mixture) while you are flying  as you climb to higher altitudes.

  

 Also check if the carb. slide will open      past  the FULL open position.     If the slide will go past the  FULL open position then the fuel flow will be increased during FULL throttle but  no additional air and will richen the mixture during FULL throttle  application.    This automatically gives a slightly rich mixture  during take off and climb when you are using full throttle.

  

  

  

  

  

  

  

  

 In a message dated 12/15/2007 10:34:55 A.M. Pacific Standard Time,  jhauck(at)elmore.rr.com writes:

  	  Quote: 	
		     DBforfun:

    

   Won't that down EGT across the board?

    

   Ed D said his EGT is 1100 at 5800, but high in midrange    rpm.  

    

   I would think changing needle position or needle or needle    jet size would influence change in midrange.

    

   john h

   mkIII - A bit rusty on 2 cycle tuning.  Flying 4    strokes since 1994.

    

    

    	  Quote: 	
		       

 

	
	


 

  



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

tkrolfe(at)toast.net
Guest

Posted: Sat Dec 15, 2007 11:43 am Post subject: High Egt's

DAquaNut(at)aol.com (DAquaNut(at)aol.com) wrote:  	  Quote: 	
		               

        Gang,

    

        My 447 Firefly Has always been plagued by EGT's at or over 1200* between 4000 rpm and 5400 rpm. If I put in more pitch, that cools EGT's a bit but causes CHT's to increase.  

     CHT's are already as high as 400* at times so adding more pitch is not the answer. I have the prop pitched for 6250 static.   The  EGT  temps are higher now that I am flying in 50* weather.  My main jet is 165 , needle jet.270, jet needle 15k2, with clip in the lowest position. I have searched the archives all afternoon and have not found a solution. It seems that going to a .272 needle would help.

      Anyone have a similar problem and solve it ?

    

                      Ed   ( Firefly 062) 

   

 	
 

 Ed,    

 

 Two things to consider.  Your gauges are probably not certified for accuracy and can vary.  Even the senders can vary.

 

 Second -  I changed my needle to an 11G2 a long time ago because of the advice of a gentleman on this list.  Check the archives.  It gave me better mid range performance as he said it would.  I run it in the third notch from the top.  

 

 As my guru ( Willie) 2 cycle flying buddy keeps telling me, forget the gauges and read the plugs.  They tell all !

 

 Might want to adjust you prop for a little higher static rpm.  I run a fixed Tennessee wood prop at a flying dynamic of 6450 rpm.

 

 Terry -  FireFly #95  770 hr.s

    [quote][b]

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Sat Dec 15, 2007 11:47 am Post subject: High Egt's

At 12:02 PM 12/15/2007, you wrote:

  	  Quote: 	
		  Put in a larger Main jet. This will bring your temps down.

  

 Order a Parts Catalog from California Power Systems. They are a Rotax authorized dealer and in their catalog there is a very big section devoted to the "Care and Feeding of Rotax engines". The articles in this section are excellent for trouble shooting and fixing most problems with Rotax engines. They are very well written and are in plain English that almost anyone can understand. 

  

 http://www.800-airwolf.com/

  

 Good luck.

 	




 The articles are also on line now



  http://www.800-airwolf.com/articles.htm

     [quote][b]

_________________
Possum

rowedenny(at)windstream.n
Guest

Posted: Sat Dec 15, 2007 12:07 pm Post subject: High Egt's

John,

 I agree with you, the main jet is probably fine.

  

 Denny

 [quote]   ---

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Sat Dec 15, 2007 12:47 pm Post subject: High Egt's

X-SpamReason %%SpamReason%%: 



 	  Quote: 	
		   Welcome to the wonderful world of Adolf's revenge....


	


Except for the fact that the Germans perfected the type....



Sir Dugald Clark (1854 - 1932) designed the first two-stroke 

engine in 1878 and patented it in England in 1881.



So much for English friends.



(I really do like my two strokes tho!)



Jim Baker

580.788.2779

Elmore City, OK

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sat Dec 15, 2007 1:18 pm Post subject: High Egt's

Gang,

     I had the same problem that he was  describing with his 447. I could get it under control everywhere except the mid  range. When I cut the power the EGT would spike. I finally had to learn to land  at higher RPM's until I found that I could lower the EGT's by pulling on the  enrichner circuit when I cut the power to the midrange part of the needle. I  finally bought the next size jet needle and had no more trouble. >From what  I have read he has done all the things that would normally work with no success.  His only recourse is to get a midrange jet that delivers more fuel. I always  attritibuted the problems that I had to the altitude. This change of the needle  jet may well affect the main jets that you will use as well. With a silencer on  mine I ended up using a 147 main jet, and a (I think) 157 without. I will assure  you that he is not imagining things. Mine was a real pain in the butt. The 503  that I now have was a piece of cake to get adjusted.

 Larry C

 [quote]   ---

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DAquaNut(at)aol.com
Guest

Posted: Sat Dec 15, 2007 8:47 pm Post subject: High Egt's

Gang,

  

      Thanks for the EGT' replies. I plan to order some  Jet needles Mon Morn and hope to have a positive report as to the result.

  

  

  

            Ed  Diebel  (Firefly #62)

  

    Do Not Archive



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

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