carburator -mixture check
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dave

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carburator -mixture check
« on: January 13, 2005, 08:45:26 PM »
hello all,
   i am having abnormal readings on my EGT ..and i already have changed to new probes..
   im suspecting the carburator..DOES ANYONE KNOW how to check IF THE CARB IS ADJUSTED PROPERLY?
  I HAVE a LYCOMING 0-235 C1B...THAT IS USING A MARVEL SCHEBLER.. MA-3A ...ALL STOCK
   CAN ANYONE ASSIST....IM ALSO THINKING OF REMOVING IT..AND MAYBE GETTING A "QUICK KIT"....IT DOES HAVE 450 HOURS ON IT....
   ANY ADVISE IS GREATLY APPRECIATED... :(
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DJ

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carburator -mixture check
« Reply #1 on: January 13, 2005, 09:47:58 PM »
Not enough data.
If you still have the same ststic RPM, and max RPM, and idle. I would not think it is the Card. Those things are bullet proof.
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sbschlam

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Carb Mixture Check
« Reply #2 on: January 14, 2005, 12:12:32 AM »
1.  agree with previous reply, not enough info,  however

- you could check plugs and exhaust pipes for lots of black carbon , which would be signs of a rich mixture.

- the easy adjustments to the Carb are idle mixture adjustment and idle speed adjustment. (External adjustments ). To restate the obvious the idle mixture adjustment only affects the mixture at IDLE rpms.  

-  Somewhat more involved, but still not too difficult is float level adjustment, which controls mixture in normal operating range.

For starters I recommend you do some reading.  Try www.precisionairmotive.com website, Support, FAQ.  They also have a tutorial / exerpts from the MSA handbook.  A short read will give you a pretty good understanding of the MA3SPA carbs exact functioning. Better yet buy the handbook and read the whole thing If you are thinking of working on your own carb.  This will cost you 15 bucks and an evening or two of reading.  Heed the WARNING.  If you don't know what you are doing, get some help from someone who does.
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Offline Jack

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Re: carburator -mixture check
« Reply #3 on: January 14, 2005, 12:43:10 PM »
Quote from: "dave"
hello all,
   i am having abnormal readings on my EGT ..and i already have changed to new probes..
   im suspecting the carburator..(


Need more data. Are you leaning?  EGT numbers can change with ambient conditions and altitude.

These carbs are pretty basic.  How do your exhaust stacks look after a flight?  Upon shutdown, with idle cutoff, do your Rs go up or down??

I normally find most folks aren't leaning properly.

Jack
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dave

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carburator mixture check
« Reply #4 on: January 14, 2005, 02:33:57 PM »
:cry:
  hi guys...,
      the info i need is ..what should be the EGT lean /peak  range when checking the mixture on the CARB ( on the ground)..like when it is newly installed..
  my egt  readings are actually jumping up and down...ERRATIC and altitude or rpm has very little effect   on it...the engiine does change sound ..a little....
  its not the egt gauge...i already swapped .....
   it might the mixture needle or jet....changing settings...
   so if someone...knows what the correct "MIXTURE' adjustment./ precedure..is.....welll  thank you  :lol:
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dave

  • Guest
carburator mixture check
« Reply #5 on: January 14, 2005, 02:33:57 PM »
:cry:
  hi guys...,
      the info i need is ..what should be the EGT lean /peak  range when checking the mixture on the CARB ( on the ground)..like when it is newly installed..
  my egt  readings are actually jumping up and down...ERRATIC and altitude or rpm has very little effect   on it...the engiine does change sound ..a little....
  its not the egt gauge...i already swapped .....
   it might the mixture needle or jet....changing settings...
   so if someone...knows what the correct "MIXTURE' adjustment./ precedure..is.....welll  thank you  :lol:
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Anonymous

  • Guest
Re: carburator mixture check
« Reply #6 on: January 14, 2005, 05:02:55 PM »
Quote from: "dave"
:cry:
  hi guys...,
      the info i need is ..what should be the EGT lean /peak  range when checking the mixture on the CARB ( on the ground)..like when it is newly installed..
  my egt  readings are actually jumping up and down...ERRATIC and altitude or rpm has very little effect   on it...the engiine does change sound ..a little....
  itl:


I don't check my EGT readings on the ground.  Your want a smooth running motor during your mag check.  Then check your max static RPM either stopped or on the takeoff roll.  As your temps, pressures, and mags check out.  EGT is more for leaning airborne.  I don't have a fuel flow gauge on this bird, otherwise would include it.

Ain't no hard and fast numbers for an EGT range.  I can drop 200 degrees in EGT from 4,500' at 10,500'.

Now when I lean,  I pull the mixture back till she stumbles some, check EGT and then add a lil rich mixture to drop her 20-40 degrees and it feels like its ripping along.  Leaning in small birds is one of those touchy feely things you have to develop.

If your motor is running pretty smooth, temps and pressures are pretty stable.  Ain't sure you got much of a problem.

Good luck;

Jack
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