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The Surging Continues....Help

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bmiles

Joined: 17 Jan 2010
Posts: 12

Posted: Sat Feb 06, 2010 11:35 am Post subject: The Surging Continues....Help

Here are my symptoms.  It's 54 Degrees outside and my Chang surges in the climb and once I'm level at 5500 I started messing with it so I can explain whats wrong.  



Once level the surging is more prominent when I ease the throttle forward, almost as if it wants to cut off but catches again.  My Manifold Pressure stays the same, however the RPM is going up and down along with the surg. 



I used one hand and held the Prop forward and pushed the throttle forward again and it surged again but not as bad as without holding the prop forward.



The prop seal was changed 3 weeks ago, that might be it or could it be my Governor going bad?



Also when I landed I throttle forward and it just about died...So I got this crazy idea and left the primer in the up position and shove the throttle forward and it seemed ok.  I did not do that in flight.......



Any thoughts, be gentle mit me plz, It's my second time posting.  Thanks

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sat Feb 06, 2010 1:47 pm Post subject: The Surging Continues....Help

what have you tried so far?

On Feb 6, 2010, at 2:35 PM, bmiles wrote:



 	  Quote: 	
		   



 Here are my symptoms.  It's 54 Degrees outside and my Chang surges  

 in the climb and once I'm level at 5500 I started messing with it so  

 I can explain whats wrong.



 Once level the surging is more prominent when I ease the throttle  

 forward, almost as if it wants to cut off but catches again.  My  

 Manifold Pressure stays the same, however the RPM is going up and  

 down along with the surg.



 I used one hand and held the Prop forward and pushed the throttle  

 forward again and it surged again but not as bad as without holding  

 the prop forward.



 The prop seal was changed 3 weeks ago, that might be it or could it  

 be my Governor going bad?



 Also when I landed I throttle forward and it just about died...So I  

 got this crazy idea and left the primer in the up position and shove  

 the throttle forward and it seemed ok.  I did not do that in  

 flight.......



 Any thoughts, be gentle mit me plz, It's my second time posting.   

 Thanks





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 85089#285089

ggg6(at)att.net
Guest

Posted: Sat Feb 06, 2010 3:44 pm Post subject: The Surging Continues....Help

dsavarese0812(at)bellsout
Guest

Posted: Sun Feb 07, 2010 6:46 am Post subject: The Surging Continues....Help

Have you pulled the little finger screen on the right side of  the nose case forward of the prop governor to make sure it completely  clean?  With the RPM going up and down, it sounds like it might be in the  prop governor.  But before you R&R the prop governor, check the  finger screen and also make sure your prop hub counter weights move freely when  the prop hub dome and piston are removed.  When was the last time you  removed the blades at the castellated nuts and cleaned and repacked the prop hub  bearings?

 Dennis

  

 [quote]   ---

viperdoc(at)mindspring.co
Guest

Posted: Sun Feb 07, 2010 10:02 am Post subject: The Surging Continues....Help

The other places to look are the carburetor diaphragm, the primer lines to the super charger, seals on the primer, primer/ system line connections, system/ primer lines, prop governor cable attachments, the copper sleeve guide, the c clamps on the fuselage from the lever to the governor, fuel filter screens, fuel lines for flappers, fuel lines for leaks, fuel pump for oil leaking through the seal between the oil pump and the fuel pump and intake collars at the cylinder and the super charger.   

Since I have a YAK, I’m not sure what you mean by leaving the primer in the up position. Since in the YAK, the up position is the center neutral position that closes the ports so fuel cannot pass through to the system side or the primer side. If leaving your primer in the neutral position does not recreate the problem, then it comes down to are you getting air in the line somewhere.  The 50 and 52 ‘s primer hand pumps are reversed on position. Centered with the indicator up at 1200 o’clock positon isolates both sides (turns off both sides). Leaving the knob turned to the system or the primer side could cause the engine to run rough.  

Another place to check is the cables to the prop governor along with all the c clamps that anchor the copper sleeve the cable slides in to the fuselage. That also manifested itself as a wondering prop RPM. I could not get the prop to fully cycle back to 51-55% during run ups and I would have the prop rpm increase in a dive. That was a different problem from the surging experienced at 5500 ft when the power was pushed up. That was solved by replacing the carburetor diaphragm. In cruise, there seemed to be a variation in power (surging) with  observed variations in the RPM by 5% or so on the gauge. When I pushed the power up to 100% at altitude, the engine balked and sputtered nearly quitting  but eventually came up to power. It seemed to like 70% better than 80%. That has resolved with changing the diaphragm.   

I had something similar with a flapper in the fuel line from the “sphere” fuel flow equalizer to the carburetor.  We found some 1/2 cm to 1 cm hose fragments had clogged the finger fuel screen at the carburetor. Understood the Chang does not have a carburetor filter screen.   

After all that, I also changed the springs in my prop governor still chasing the surging problem. That did not solve the problem either.  

 Even went so far as to change the prop governor itself. That did not help either. Pulled the dome on the prop and checked the seals with no help there either.   

Found an interesting case of Russian Afro engineering as it pertained to my prop governor cable while chasing this “surging” problem. Instead of running a one piece copper tube for the sleeve, they ran two segments. The two ends were anastamosed inside a larger bore piece of  tubing held together with a  lone c clamp. Over time ( 146 hours since taking delivery), the c clamps on the fuselage had loosened up allowing the cable guide end from the anastamosis segment forward to the prop governor  to migrate forward. So now the cable would form an S curve between the two ends where a gap between the two copper tube guides were now. Fixing that required pulling the Aux and main fuel tanks out of the 50 and repairing the guide tubing. After doing this, I have not had any surging sensations or variation in the % RPM  on the gauge.  

That is just some of the tribulations I have been through with my 50 while chasing a “surging engine”.  

So here is a list of what has been done to  solve the surging problem or the varying fluctuations in % RPM (by me-call it the shotgun approach over a span of 2 years as different parts of this equation have arisen):  

Pulled the carburetor  only to find the fuel filter screen had fragments of the inner liner from the fuel line in it and could have been cleaned without pulling the carb. This came after the engine quit 50 feet off the runway on take-off resulting in a dead stick landing without damage to the A/C or myself. Funny thing,  she started and ran fine back in the chocks with the exception wanting to surge at 80-90% when run up. This was done with the aircraft tied down and chocked. Losing the engine came without any prior warning.  

Replaced the primer lines after finding a small leak in the line at the base of the fitting at the firewall connection    

Replaced the fuel pump after seeing a mixture of oil and fuel drip down on my knee from the overflow valve while I was under the aircraft tightening the intake collars –seems the seal on  the driveshaft was leaking allowing oil to seep down into the fuel pump. Had seen blue oily drops on the drop pan under the chin of the plane earlier but could not find a source. The drop pan was in place under the nose to prevent oil from collecting on my hanger floor.  

Replaced the o ring seal on the primer after fuel leaked out during priming that was not solved by tightening the knurled nut.  

Pulled the prop governor-replacing it with another along with changing out the springs for the stiffer set offered by Jim Kimbell  

Replaced the seals on the prop dome and piston – Bearings had been service the previous year.   

Pulled the finger screen in the capillary line to the prop – was clean  

Screwed with the idler arm on the prop governor because I could not get the prop to fully cycle after calling myself checking all the cable attachments except for the one I did not know about. The Russian Afro engineered one below and behind the fuel tanks hidden from sight. Did not find that one until the very last when I was trying to advance the cable end by pulling back on the prop lever. Seems the cable only moved about an inch. That sent me on a chase through the fuselage from the governor back to the prop lever attachment at the consol in the cockpit.  

Lastly repair the copper cable guide and tighten all the c clamps holding the prop governor cable. Then put the F(at)#$%^& fuel tanks back in along with re-attaching the lines making sure to use fuel lube on the threads. Making sure none got on the nipples so I would have an airtight seal without gumming up the fuel screen filters. ( Oh yeah, I pulled those and made sure they were clean too.)   

This along with checking and tightening any loose collars on the intakes at the cylinders and the supercharger.  

Also tighten any loose exhaust collars. A couple of each, intake and exhaust collars were found to be very slightly loose…less than a quarter turn. Doubt that had anything to do with the surging.  

Now having done all that, I have not the foggiest idea what solved the problem but it is gone…for now.  

Not sure I would spend much time flying her if she is surging to the point of losing power in flight though. I’ve been a test pilot enough over the past 6 years.  

Good Luck.   

Disclaimer?: This was only intended to state what has been tried by myself to solve a “surging” problem that was experienced by myself. The writing of this epistle has only been intended to state what has been done by myself to resolve a problem I perceived and or experienced. This epistle was not in any way intended to imply that the problem currently being experienced it is in any way related. Your findings and resolution of this problem may vary from my findings. But good luck anyway…:^))  

   

Doc  

       

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of A. Dennis Savarese

 Sent: Sunday, February 07, 2010 8:42 AM

 To: yak-list(at)matronics.com

 Subject: Re: The Surging Continues....Help  

  

  

     

Have you pulled the little finger screen on the right side of the nose case forward of the prop governor to make sure it completely clean?  With the RPM going up and down, it sounds like it might be in the prop governor.  But before you R&R the prop governor, check the finger screen and also make sure your prop hub counter weights move freely when the prop hub dome and piston are removed.  When was the last time you removed the blades at the castellated nuts and cleaned and repacked the prop hub bearings?  

    

Dennis  

    

   

   	  Quote: 	
		      

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

    

From: bmiles (miles(at)wambua.com)   

    

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

    

Sent: Saturday, February 06, 2010 1:35 PM  

    

Subject: The Surging Continues....Help  

    

   

  

--> Yak-List message posted by: "bmiles" <miles(at)wambua.com (miles(at)wambua.com)>

 

 Here are my symptoms.  It's 54 Degrees outside and my Chang surges in the climb and once I'm level at 5500 I started messing with it so I can explain whats wrong.  

 

 Once level the surging is more prominent when I ease the throttle forward, almost as if it wants to cut off but catches again.  My Manifold Pressure stays the same, however the RPM is going up and down along with the surg. 

 

 I used one hand and held the Prop forward and pushed the throttle forward again and it surged again but not as bad as without holding the prop forward.

 

 The prop seal was changed 3 weeks ago, that might be it or could it be my Governor going bad?

 

 Also when I landed I throttle forward and it just about died...So I got this crazy idea and left the primer in the up position and shove the throttle forward and it seemed ok.  I did not do that in flight.......

 

 Any thoughts, be gentle mit me plz, It's my second time posting.  Thanks

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=285089#285089

 

 

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       [quote][b]

dsavarese0812(at)bellsout
Guest

Posted: Mon Feb 08, 2010 4:53 am Post subject: The Surging Continues....Help

Doc,

 The CJ does have a carburetor filter screen.  But it's  like the coarse filter screen on the Yak 52.  The carburetor on CJ is  connected directly to this fuel filter.

  

 Fuel related surging will typically affect manifold pressure  as well as RPM.

  

 A clogged little finger screen on the nose case will cause  more problems than one would believe when it comes to RPM related  problems.  Believe it or not, many people never check that little  guy.

  

 Also prop hub bearings that haven't been cleaned and repacked  for a long, long time will affect the ability of the prop blades to move to  coarse pitch (lower RPM) via the counter weights and back to fine pitch via oil  pressure.  

 Dennis

  

 [quote]   ---

UFO

Joined: 29 Jul 2007
Posts: 18
Location: Salt Lake City , Utah

Posted: Mon Feb 08, 2010 7:57 am Post subject: The Surging Continues....Help

Hi all.  Dennis, my CJ has been experiencing the same surge problems.  It’s currently finishing up on the conditional inspection and my mechanic checked the prop governor as that was my first suspicion.  He said that other than a small amount of grease and dirt, it seemed fine.  We’re going to keep an eye on it and I’ll let you and the list know the results.  Thanks to everyone’s input, I’ll also have him check the filter and flapper etc.  By the way… just saw the army green Chang with yellow and green tail that made a successful emergency landing in Arizona today with it’s nose stuck in a n outdoor restroom.   Thankfully both passenger and pilot are fine.  (Other than they’ll probably receive a new call sign and it won’t be glamorous.)  Good job you guys and we’re glad you’re still with us.       

       [quote][b]

_________________
"Pilots take no special joy in walking, pilots like flying." - Neil Armstrong

wlannon(at)persona.ca
Guest

Posted: Mon Feb 08, 2010 9:54 am Post subject: The Surging Continues....Help

You left the primer in the up position and ----it seemed OK.

If by the "UP" position you mean the center position then that may very well 

fix the problem.  The center position is OFF, the primer is closed. This is 

the correct position for flight. Left or right of center is "ON" for priming 

but if not closed after priming this will cause an over-rich mixture that 

will result in the symptons you describe.



Walt

---

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Tue Feb 09, 2010 7:47 pm Post subject: Re: The Surging Continues....Help

There is a cap on the primer that sometimes can get very loose and it can be hard to tell It has the hole in it for the plunger. Just a thought don't know if it would matter

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Tue Feb 09, 2010 7:56 pm Post subject: Re: The Surging Continues....Help

Also, is the fuel vent line a home for mud daubers??

barryhancock

Joined: 09 Oct 2008
Posts: 285

Posted: Wed Feb 10, 2010 7:14 am Post subject: Re: The Surging Continues....Help

Yes!  Or so I've been told by those who have the great privilege of living in parts hospitable to those little buggers. Fix some wire mesh to it.  While you are at it, filing it flat also appears to help with the fuel imbalance problem.



Barry

_________________
Barry Hancock
Worldwide Warbirds, Inc.
www.worldwidewarbirds.com

bmiles

Joined: 17 Jan 2010
Posts: 12

Posted: Wed Feb 10, 2010 8:39 am Post subject: Re: The Surging Continues....Help

Great feedback.  It's been very cold for us here and working in a freezing hanger is not attractive.  Marcus and I will trouble shoot today hopefully and I will post our findings.  BTW, Jon and I checked my wobble pump briefly and noticed it was not pumping, hmmmmm.  Hope its a quick fix.  



Will post my findings.  Thanks guys

pilotdog57(at)aol.com
Guest

Posted: Wed Feb 10, 2010 12:48 pm Post subject: The Surging Continues....Help

Check the header tank vent- it may be blocked and preventing the wobble pump from picking up fuel. Doug Zeissner N114DZ

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