Hi Remi
First and foremost you don't want to be running lean when you are making "a lot"
of BTUs.
Make sure your carb jets and passages are not clogged with "carb snot" and your
diaphragm is not ripped or torn.
If your forward cylinders run a little rich at lower RPMs, so be it, but at take
off power your real interest is you are not running lean at all. Best taint
slight towards richer at full power. Rotax has you check older 914s and newer
ones with intake modifications (intercooler is a intake modification for carbon
monoxide content and list a minimum, in other words they want to make sure you
are rich enough at higher power settings. Pay very careful attension that you
are not lean at high power.
Then lower power settings, I am an advocate to run them to point where engine
does
not hesitate. After carbs are verified "OK" and you sync them, you can fool
with airscrew adjustment, turning in richens mixture and out leans them up.
Go a little at a time until engine hesitates then go a bit richer. This is only
going to be in effect at idle and not much over. Black can accumulate from lower
speed operations.
*Thus go over carbs and connections with a fine tooth comb
*Verify at 105% and at 85% you are not too lean on any cylinder, easier said
than
done, if you have EGTs you can temporarily turn off fuel and see if you ar
rich of peak, if you don't get a rise, you may be lean or even lean of peak,
running
peak and lean of peak at high power settings goes against long engine life
*Cruise is where you spend most of your time, thus remember that running mogas
does not give a very good inducation of mixture on plugs, run some 100LL and
cruise
and land as quick as possible and take a plug reading, see what things look
at. You can take a plug reading then at taxi power settings and see what
that looks like. A bit hard on motor but to take a good full power plug reading,
you would need to have full power for a while, then turn off motor after not
too long a cool down and take a reading. Unless a Tri or Mono glider you best
not want to a deadstick on a Mono short wing?
Ron P.
Visit - www.EuropaOwners.org
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