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Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed May 23, 2012 5:24 pm Post subject: engine woes

My engine is not running quite "right".



 It's a Cuyuna ULII-02 on my UltraStar.  Always ran great (though at the end of last season I had to replace the rear crankshaft seal which was leaking, and it again ran great after that).  Last week, after flying to another airport and filling up there (with avgas), on the flight home it started behaving like it was running rich, wouldn't hold cruise rpm without sagging so I was constantly jockeying the throttle.  Today, I couldn't get the proper 6500 rpm static, more like 6100, and after some extended low throttle running it wouldn't accelerate to full throttle, just wanted to quit.  That's happened before if set to rich and dropping the needle one notch fixed that, but the WOT rpm is still low.  EGT is also lower than it should be  I dropped a jet size (one size smaller than it should be for the current air temperature) and it's a _bit_ better but still not right.  Fuel consumption also seems to be up but I haven't quantified it.  Avgas does tend to run a bit richer than ethanol contaminated autogas but now the tank is half avgas and half autogas and it's still running crappy.



 I tried running without the air filter, no change.  Spark plugs look OK.  I might suspect the float level but how would that change?  Float needle was replaced last year with a viton needle, shouldn't be bad yet.



 Any ideas?



 -Dana    [quote][b]

ceengland(at)bellsouth.ne
Guest

Posted: Wed May 23, 2012 5:51 pm Post subject: engine woes

On 05/23/2012 08:11 PM, Dana Hague wrote:      	  Quote: 	
		         My engine is not running quite "right".

         

         It's a Cuyuna ULII-02 on my UltraStar.  Always ran great (though         at         the end of last season I had to replace the rear crankshaft seal         which         was leaking, and it again ran great after that).  Last week,         after         flying to another airport and filling up there (with avgas), on         the         flight home it started behaving like it was running rich,         wouldn't hold         cruise rpm without sagging so I was constantly jockeying the         throttle.  Today, I couldn't get the proper 6500 rpm static,         more         like 6100, and after some extended low throttle running it         wouldn't         accelerate to full throttle, just wanted to quit.  That's         happened         before if set to rich and dropping the needle one notch fixed         that, but         the WOT rpm is still low.  EGT is also lower than it should be          I dropped a jet size (one size smaller than it should be for the         current         air temperature) and it's a _bit_ better but still not right.          Fuel         consumption also seems to be up but I haven't quantified it.          Avgas         does tend to run a bit richer than ethanol contaminated autogas         but now         the tank is half avgas and half autogas and it's still running         crappy.

         

         I tried running without the air filter, no change.  Spark plugs         look         OK.  I might suspect the float level but how would that         change?  Float needle was replaced last year with a viton         needle,         shouldn't be bad yet.

         

         Any ideas?

         

         -Dana

     	
     Well, for a little wild speculation (& a very easy 1st step),     I'd change the plugs. Avgas is really nasty on plugs (and valve     guides, and....etc etc). The guys flying rotaries on experimentals     who run avgas have to replace plugs every 20-30 hrs. The damage     can't be seen without a microscope, but the symptom a major sag in     power. The thing that doesn't seem consistent (unless it really is     extremely rich) is the drop in EGT. Avgas burns so much slower that     it usually causes EGT to go up; it's still burning in the exhaust.

     

     Anyway, a plug swap is about as simple as you can get for     troubleshooting.

     

     Charlie

      [quote][b]

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed May 23, 2012 6:24 pm Post subject: engine woes

At 09:51 PM 5/23/2012, Charlie England wrote:

  	  Quote: 	
		  Well, for a little wild speculation (& a very easy 1st step), I'd change the plugs. Avgas is really nasty on plugs (and valve guides, and....etc etc). The guys flying rotaries on experimentals who run avgas have to replace plugs every 20-30 hrs. The damage can't be seen without a microscope, but the symptom a major sag in power. The thing that doesn't seem consistent (unless it really is extremely rich) is the drop in EGT. Avgas burns so much slower that it usually causes EGT to go up; it's still burning in the exhaust. 	


 I would have changed the plugs but I didn't have a feeler gage handy to gap them, and I know (from recent experience) that improperly gapped plugs can cause a 500 rpm drop.  I do plan on changing the plugs next time I go out to fly, even though they probably have about 5 hours on them.



 Avgas doesn't actually burn slower; it's just more resistant to detonation so EGT shouldn't be affected.  However, the ethanol in car gas does affect the mixture... it burns leaner, my experience is that it's worth about half a jet size.



 -Dana

 --

 The city is not a concrete jungle.  It is a human zoo.  

    [quote][b]

captainron1(at)cox.net
Guest

Posted: Thu May 24, 2012 1:18 am Post subject: engine woes

I had a similar problem that in fact forced me down, it was an air leak from a crack in the primer bulb.



Ron (at) KFFL





================================================

---- Dana Hague <d-m-hague(at)comcast.net> wrote: 



=============

My engine is not running quite "right".



It's a Cuyuna ULII-02 on my UltraStar.  Always ran great (though at the end 

of last season I had to replace the rear crankshaft seal which was leaking, 

and it again ran great after that).  Last week, after flying to another 

airport and filling up there (with avgas), on the flight home it started 

behaving like it was running rich, wouldn't hold cruise rpm without sagging 

so I was constantly jockeying the throttle.  Today, I couldn't get the 

proper 6500 rpm static, more like 6100, and after some extended low 

throttle running it wouldn't accelerate to full throttle, just wanted to 

quit.  That's happened before if set to rich and dropping the needle one 

notch fixed that, but the WOT rpm is still low.  EGT is also lower than it 

should be  I dropped a jet size (one size smaller than it should be for the 

current air temperature) and it's a _bit_ better but still not right.  Fuel 

consumption also seems to be up but I haven't quantified it.  Avgas does 

tend to run a bit richer than ethanol contaminated autogas but now the tank 

is half avgas and half autogas and it's still running crappy.



I tried running without the air filter, no change.  Spark plugs look OK.  I 

might suspect the float level but how would that change?  Float needle was 

replaced last year with a viton needle, shouldn't be bad yet.



Any ideas?



-Dana 

--

Ron (at) KFHU

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu May 24, 2012 2:55 am Post subject: engine woes

At 05:17 AM 5/24/2012, Ron  (at)  KFHU wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: "Ron  (at)  KFHU" <captainron1(at)cox.net>



 I had a similar problem that in fact forced me down, it was an air leak from a crack in the primer bulb. 	


 But an air leak would cause a lean condition... all my symptoms point to rich running.



 -Dana

 --

 There is always a law against doing anything interesting.    

    [quote][b]

williamtsullivan(at)att.n
Guest

Posted: Thu May 24, 2012 3:32 am Post subject: engine woes

Dana- This might be a really dumb question, but does your gas smell like gas?  My 447 started OK, but no full RPM.  I am checking carb settings, and for crud, before going further.  But, using the same gas, I have a Husky brush saw giving me trouble.  This is new gas, too.  It doesn't smell right, so maybe a bad load?  Too much ethanol?  Both of us got gas through the New Haven terminal.  Might not affect a car, with computers adjusting things.  Something to think about.  KISS.  My truck seems to be sucking a lot of gas, too.



                                           Bill  Sullivan



                                         



  



--- On Thu, 5/24/12, Dana Hague <d-m-hague(at)comcast.net> wrote:

 	  Quote: 	
		  

From: Dana Hague <d-m-hague(at)comcast.net>

Subject: Re: engine woes

To: kolb-list(at)matronics.com

Date: Thursday, May 24, 2012, 6:50 AM



 At 05:17 AM 5/24/2012, Ron  (at)  KFHU wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: "Ron  (at)  KFHU" <captainron1(at)cox.net>



 I had a similar problem that in fact forced me down, it was an air leak from a crack in the primer bulb. 	


 But an air leak would cause a lean condition... all my symptoms point to rich running.



 -Dana

 --

 There is always a law against doing anything interesting.    

     	  Quote: 	
		  http://w="nofollow" target="_blank" href="http://forums.matronics.com">http://www.matronics.com/contribution">http://www.matronics.com/contribution============


	


	
 [quote][b]

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu May 24, 2012 4:18 am Post subject: engine woes

I doubt it... the trouble seemed to start after filling up with avgas (which has pretty good quality control and no ethanol) at Simsbury.



 -Dana



 At 07:31 AM 5/24/2012, william sullivan wrote:

  	  Quote: 	
		    Dana- This might be a really dumb question, but does your gas smell like gas?  My 447 started OK, but no full RPM.  I am checking carb settings, and for crud, before going further.  But, using the same gas, I have a Husky brush saw giving me trouble.  This is new gas, too.  It doesn't smell right, so maybe a bad load?  Too much ethanol?  Both of us got gas through the New Haven terminal.  Might not affect a car, with computers adjusting things.  Something to think about.  KISS.  My truck seems to be sucking a lot of gas, too. 	


 --

 "If you want to build a ship, then don't drum up men to gather wood, give orders, and divide the work. Rather, teach them to yearn for the far and endless sea." - Antoine de Saint-Exupéry

    [quote][b]

byoungplumbing(at)gmail.c
Guest

Posted: Thu May 24, 2012 4:26 am Post subject: engine woes

I had a similar problem that in fact forced me down, it was an air leak  from a crack in the primer bulb.

But an air leak would cause a lean  condition... all my symptoms point to rich running.



-Dana

 --

  

 >>>>>>>>>>>>>>>...

  

 could there be a hair, grain of dirt, or other  debris,  in the float needle.   this could cause a high fuel  level in the float bowl.  it may not be bad enough for the float bowl to  over fill and run out,  but run rich.

  

 just thinking out loud.

  

 boyd y

  



   [quote][b]

williamtsullivan(at)att.n
Guest

Posted: Thu May 24, 2012 4:33 am Post subject: engine woes

You should have called me when you were there.  It's 10 minutes away.  I wonder where the avgas comes from, and who mixes it?



--- On Thu, 5/24/12, Dana Hague <d-m-hague(at)comcast.net> wrote:

 	  Quote: 	
		  

From: Dana Hague <d-m-hague(at)comcast.net>

Subject: Re: engine woes

To: kolb-list(at)matronics.com

Date: Thursday, May 24, 2012, 8:17 AM



 I doubt it... the trouble seemed to start after filling up with avgas (which has pretty good quality control and no ethanol) at Simsbury.



 -Dana



 At 07:31 AM 5/24/2012, william sullivan wrote:

  	  Quote: 	
		    Dana- This might be a really dumb question, but does your gas smell like gas?  My 447 started OK, but no full RPM.  I am checking carb settings, and for crud, before going further.  But, using the same gas, I have a Husky brush saw giving me trouble.  This is new gas, too.  It doesn't smell right, so maybe a bad load?  Too much ethanol?  Both of us got gas through the New Haven terminal.  Might not affect a car, with computers adjusting things.  Something to think about.  KISS.  My truck seems to be sucking a lot of gas, too. 	


 --

 "If you want to build a ship, then don't drum up men to gather wood, give orders, and divide the work. Rather, teach them to yearn for the far and endless sea." - Antoine de Saint-Exupéry

     	  Quote: 	
		  http://www.matronics.c==================


	


	
 [quote][b]

John Hauck

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

Posted: Thu May 24, 2012 4:47 am Post subject: engine woes

could there be a hair, grain of dirt, or other debris,  in the float

needle.   this could cause a high fuel level in the float bowl.  it may not

be bad enough for the float bowl to over fill and run out,  but run rich.

 

boyd y

 

Folks:



My Cuyuna ULII02 was very sensitive to over-rich condition.



I installed a CPS in-flight adjustable main jet on the Mikuni carb.  Just a

tad rich over optimum power settings, the Cuyuna would shut down, just like

hitting the kill switch.  Never had an engine that was so sensitive to a

slightly over-rich condition.



The Cuyuna, mounted on my 1984 Ultrastar, consumed a lot of 100LL.  It ran

the same on 100LL as it did on 93 octane mogas without alcohol.  My 447

operated the same, as well as the 80 and 100 hp Rotax 912.  Only noticeable

difference between 100LL and mogas on the two strokes was slightly lower

EGT.  Don't know about the 4 strokes, I don't run an EGT gauge.



john h

mkIII

Titus, Alabama

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

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Thu May 24, 2012 4:58 am Post subject: Re: engine woes

A couple thoughts - does it have a metal float or a composite one? I have seen composite floats set lower than they should and cause excessive richness.



Do you have a Mikuni and does it have an enrichner circuit like the Bing? Is it possible for the seat of the device to have a leak, and let fuel seep around it?



If you have an enrichner, how is it actuated? I had a friend with a J-3 kitten and his panel mounted lever got a glitch and would not let the enrichner seat properly as the problem made the cable a bit too short.



And probably none of this is pertinent, but here's hoping.

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Thu May 24, 2012 4:59 am Post subject: engine woes

Boyd,



  Your suggestion is exactly what I was thinking, and also what I saw my instructor experience (crap in the fuel system

on my his QS II ).

  Dana, if your engine ran fine at some previous point, I would suggest NOT changing needle

settings.  You don't fix an ailing engine by readjusting it to work with what is screwing it up.  You analyze what

the problem is BEFORE you make any changes, otherwise you never truly know if you fixed the problem 

properly.





  If an engine is generally running good, and then starts running lousy, you look for the likely

causes first.  Start out by scrubbing your entire fuel system to spotless condition.  Then, verify

all the components of your electrical system (plugs, wires, connections, etc.)  Next, check compression,

followed by a timing check.

  If the problem still persists after verifying that all of the above are perfect, consider pulling the carb,

and checking to see if the float has developed a leak.  I had this happen on my Cessna Marvel-Shebler

carburetor.  The way to check for leaks in a brass float is; you get two glasses of water.  Ice cold and

microwave hot.  Hold the float underwater in the cold water for several seconds.  If there is a leak, the

shrinking air in the float will suck in a little water.  Then, take your float out of the cold, and hold it under the

hot water.  The rapidly expanding air will literally blast out that sucked-in water, creating a dirty stream of

clearly obvious filth, along with lots of bubbles.

  If the float is still in excellent shape, the dips in the cold and them hot won't make any difference.

  Consider an air leak by spraying some carb cleaner at the joint and mounting places of the carb.  Make

sure not to get close to the air inlet.  If the engine accelerates from the carb cleaner, you have an intake

leak.

  Just some thoughts.........

Mike Welch



On May 24, 2012, at 7:26 AM, b young wrote:

 	  Quote: 	
		  

I had a similar problem that in fact forced me down, it was an air leak from a crack in the primer bulb.

But an air leak would cause a lean condition... all my symptoms point to rich running.



-Dana

--

 

 	  Quote: 	
		  >>>>>>>>>>>>>>...

 
	


could there be a hair, grain of dirt, or other debris,  in the float needle.   this could cause a high fuel level in the float bowl.  it may not be bad enough for the float bowl to over fill and run out,  but run rich.

 

just thinking out loud.

 

boyd y

 



 	  Quote: 	
		  



href="http://www.matronics.com/Navigator?Kolb-List">http://www.matronics.com/Navigator?Kolb-List

href="http://forums.matronics.com">http://forums.matronics.com

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 [quote][b]

John Hauck

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

Posted: Thu May 24, 2012 5:56 am Post subject: engine woes

Do you have a Mikuni and does it have an enrichner circuit like the Bing? Is

it possible for the seat of the device to have a leak, and let fuel seep

around it?



Richard Pike

 



Richard P/Folks:



That is a good point.  Had forgotten about the leaking enricher seat.

Cannot remember if the Mikuni uses similar system as the Bing.  Those seats

get old, hard, and leak with age.  When they do, they present an over-rich

condition.



The ULII02 has CDI ign, so doubt Dana has a timing problem.



Malfunctioning float/needle valve?



Like I mentioned earlier, the ULII02 doesn't like an over-rich condition and

will shut down in a second.



john h

mkIII

Titus, Alabama

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

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu May 24, 2012 5:05 pm Post subject: engine woes

Float level, either submerged float or debris on / bad needle sounds likely, but I shut the fuel valve off while the engine was running, thinking if a high level in the bowl was the problem it would run better as the level dropped before it quit.  There was no change.  I changed the jetting not so much as a fix but as an experiment.  The floats are plastic, not brass, so that's unlikely anyway.  An air leak is also unlikely as all the symptoms point to rich running, not lean.



 Richard suggested the enrichener (yes, the Mikuni has an enrichener circuit) and that's something I intend to check... I have a new remote one that I never got around to installing.  That could very well be it... operating it at full throttle has minimal effect, though it still makes a big difference at lower throttle setting.  I'll also replace the plugs (even though they look fine) and add fresh fuel.  All of this will have to wait until after the holiday weekend, though.  I can check the compression but I don't know what the proper values are for this engine.



 -Dana



 At 08:58 AM 5/24/2012, Michael Welch wrote:

  	  Quote: 	
		  Boyd,



   Your suggestion is exactly what I was thinking, and also what I saw my instructor experience (crap in the fuel system

 on my his QS II ).



   Dana, if your engine ran fine at some previous point, I would suggest NOT changing needle

 settings.  You don't fix an ailing engine by readjusting it to work with what is screwing it up.  You analyze what

 the problem is BEFORE you make any changes, otherwise you never truly know if you fixed the problem 

 properly.



 

   If an engine is generally running good, and then starts running lousy, you look for the likely

 causes first.  Start out by scrubbing your entire fuel system to spotless condition.  Then, verify

 all the components of your electrical system (plugs, wires, connections, etc.)  Next, check compression,

 followed by a timing check.



   If the problem still persists after verifying that all of the above are perfect, consider pulling the carb,

 and checking to see if the float has developed a leak.  I had this happen on my Cessna Marvel-Shebler

 carburetor.  The way to check for leaks in a brass float is; you get two glasses of water.  Ice cold and

 microwave hot.  Hold the float underwater in the cold water for several seconds.  If there is a leak, the

 shrinking air in the float will suck in a little water.  Then, take your float out of the cold, and hold it under the

 hot water.  The rapidly expanding air will literally blast out that sucked-in water, creating a dirty stream of

 clearly obvious filth, along with lots of bubbles.

   If the float is still in excellent shape, the dips in the cold and them hot won't make any difference.



   Consider an air leak by spraying some carb cleaner at the joint and mounting places of the carb.  Make

 sure not to get close to the air inlet.  If the engine accelerates from the carb cleaner, you have an intake

 leak.



   Just some thoughts.........



 Mike Welch



 



 On May 24, 2012, at 7:26 AM, b young wrote:



  	  Quote: 	
		  

 I had a similar problem that in fact forced me down, it was an air leak from a crack in the primer bulb.

 But an air leak would cause a lean condition... all my symptoms point to rich running.



 -Dana

 --

  

 >>>>>>>>>>>>>>>...

  

 could there be a hair, grain of dirt, or other debris,  in the float needle.   this could cause a high fuel level in the float bowl.  it may not be bad enough for the float bowl to over fill and run out,  but run rich.

  

 just thinking out loud.

  

 boyd y

  



  	  Quote: 	
		  



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 What's brown and sticky? A stick!

    [quote][b]

captainron1(at)cox.net
Guest

Posted: Thu May 24, 2012 8:29 pm Post subject: engine woes

Your symptoms sounded a lot like my lean symptoms.  



Ron (at) KFFL

========================

---- Dana Hague <d-m-hague(at)comcast.net> wrote: 



=============

At 05:17 AM 5/24/2012, Ron  (at)  KFHU wrote:

 	  Quote: 	
		  



I had a similar problem that in fact forced me down, it was an air leak 

from a crack in the primer bulb.


	


But an air leak would cause a lean condition... all my symptoms point to 

rich running.



-Dana

--

There is always a law against doing anything interesting.



--

Ron (at) KFHU

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