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				 Posted: Fri Feb 07, 2014 2:16 am    Post subject: JabiruEngine-List Digest: 2 Msgs - 02/06/14 | 
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				Hello,
 
 I  not flying yet but in a conversation with another jabiru pilot, they, (2 planes, 2 jabiru's, same concern) actually reduced throw on the carb butterfly. We are talking a small amount. 
 
 It was states that they still felt the engine was a full power but the butterfly valve didn't quite make 100% open. 
 
 My conversation with them was carb airflow concerns I had while still building. The concerns where stimulates from the past 8 years of listening to this forum.  That is how this subject came up. 
 
 Anyhow, may be worth a Try only using 95% butterfly movement or at least reducing in small increments on a trial basis. 
 
 Safe flying!
 
 - Rich
 
 On Feb 7, 2014, at 2:02 AM, JabiruEngine-List Digest Server <jabiruengine-list(at)matronics.com> wrote:
 
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                            JabiruEngine-List Digest Archive
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                      Total Messages Posted Thu 02/06/14: 2
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  Today's Message Index:
  ----------------------
  
      1. 11:19 PM - Rough running Jab 3300  (Gary Eady)
      2. 11:36 PM - Re: Rough running Jab 3300  (Paul Mulwitz)
  
  
  
  ________________________________  Message 1  _____________________________________
  
  
  Time: 11:19:40 PM PST US
  From: Gary Eady <gary_eady(at)xtra.co.nz>
  Subject: Rough running Jab 3300
  
  I'm having a few issues with my Jab 3300 solid lifter engine. Intermittentl
  y, normally under load in the climb, it develops a miss in either one or ot
  her of the front cylinders. The miss/rough running only lasts between about
  10 and 20 seconds and recurs every couple of hours or so of flying - but i
  s enough to make me look around quickly for an off field landing area.=0AHa
  ve checked the resistance and condition of the HT leads and also the coils.
  All seem to be ok.=0AThe errant cylinder is easy to track via the EGT prob
  es and is always number 1 or 2 which is suddenly about 100 degrees C cooler
  than the others.=0AThe engine has 70 hours on it and starts well hot or co
  ld - is burning no oil and throws virtually no oil into the breather bottle
  .. All engine parameters are great including cylinder head temps. Except for
  this darn miss.=0A=0AAnyone else out there having or had a similar problem
  ??=0A=0A=0ARegards=0A=0AGary=0A=0ACH701,- Jab 3300A serial number 500, 70
  hours total time. Grand Rapids EIS.
  
  ________________________________  Message 2  _____________________________________
  
  
  Time: 11:36:41 PM PST US
  From: Paul Mulwitz <psm(at)att.net>
  Subject: Re: Rough running Jab 3300
  
  Hi Gary,
  
  First let me say I am no expert on engines of any sort.  So don't depend 
  on my being right.
  
  I once had some strange miss-firing because the carburetor was loose.  
  It was more dramatic than your story and only went bad when I reduced to 
  idle power for descent.
  
  The thing that comes to mind listening to your story is you are at a 
  high angle of attack.  That suggests there is something about the air 
  flow to the carburetor might be funny.  In my plane I took extra 
  measures to straighten out the air flow just in front of the 
  carburetor.  There are several ways to do this, and I don't really know 
  if any are necessary.
  
  A 3300 is a large engine for a 701.  You must get very high pitch on the 
  aircraft nose when climbing.  This suggests a possible problem with fuel 
  pressure could be involved.  Do you have a boost pump?
  
  Good luck,
  
  Paul
  Camas, WA
  Zodiac XL, Jab 3300
  
  On 2/6/2014 11:16 PM, Gary Eady wrote:
 > I'm having a few issues with my Jab 3300 solid lifter engine. 
 > Intermittently, normally under load in the climb, it develops a miss 
 > in either one or other of the front cylinders. The miss/rough running 
 > only lasts between about 10 and 20 seconds and recurs every couple of 
 > hours or so of flying - but is enough to make me look around quickly 
 > for an off field landing area.
 > Have checked the resistance and condition of the HT leads and also the 
 > coils. All seem to be ok.
 > The errant cylinder is easy to track via the EGT probes and is always 
 > number 1 or 2 which is suddenly about 100 degrees C cooler than the 
 > others.
 > The engine has 70 hours on it and starts well hot or cold - is burning 
 > no oil and throws virtually no oil into the breather bottle. All 
 > engine parameters are great including cylinder head temps. Except for 
 > this darn miss.
 > 
 > Anyone else out there having or had a similar problem??
 > 
 > 
 > Regards
 > 
 > Gary
 > 
 > CH701, Jab 3300A serial number 500, 70 hours total time. Grand Rapids EIS.
 > 
 > *
 > 
 > 
 > *
  
  
  
  
  
  
  
  
  
 
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