Hi everyone,
I promised an update so here it is.
In a nutshell, I decided to follow my eyes, which were looking at very white
rear
cylinder plugs. So I decided to move the needle from position #3 to position
#4 and enrichen the mid-range mixture.
The jury is still out since I only did two flights since the change but the
difference
is notable in terms of engine smoothness. But too early for final conclusions.
I did pull the plug and it looks a more reasonable light tan now which
I think is an improvement. I will report back on the mid-range adjustment once
I do a few flights in different conditions.
But what really caught my attention is that for the last three years, even with
changing to a new engine, I had to put up with crappy idling 912Ss (at least
by my picky standard). I always thought that that was the way these engines
idle,
particularly the high compression 912S.
Well, I finally decided to play with the idle mixture. I had moved the idle
screw
a flat or so in the past to see if anything happened but not much did. But
this time around I decided to move the screw in or out one flat at a time until
something happened. Well, what a pleasant surprise when the engine started to
get smoother as I screwed the needle in but not until you are at less than one
turn from fully closed. And I mean HUGE improvement. All the roughness went
away and now it idles smoothly.
Again, I still have to fly more with these settings but what a difference so
far.
I told a Rotax 912S owner friend of mine all this and he recommended I watch
this
video. I think it exemplifies my newly acquired conviction that the carbs in
the 912S have to be tuned beyond just the simple balancing.
https://www.youtube.com/watch?v=GxEORpdJp0w
Best,
Chris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510157#510157
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