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<DIV><FONT size=2>I have had better experience running at least 25% nitro, and
prop the engine to run around 9000 rpm. Also remember, to lean the low spead
needle, you turn the screw out. It is an airbleed adjustment. Good luck,
Terry</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=hmetzger@alternex.com.br href="mailto:hmetzger@alternex.com.br">Hugo
Henriques</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, April 04, 2003 10:47
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> YS 91 AC Adjustment
Problems.</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hi,</FONT></DIV>
<DIV><FONT face=Arial size=2>I've just installed a brand new YS 91AC in a
Midwest Little Cap and started facing some problems. The engine was properly
broke in and really performed well in the test stand. As it was installed in
the model for flight (the fuel tank was tested before and after this
experience) I noticed that the mid range was "very rich" as the engine would
take a lot of time to reach full speed. I turned in the low speed needle valve
but didn't feel any performance increase, so I decided to turn in the pump
screw in. I turned the pump screw in almost two turns, as the engine showed an
imediate response from low speed to high speed. Anyway, the low speed still
needed some fine tuning but again I didn't feel any difference turning the low
speed neddle valve in or out, unless it was fully closed. Afterwards, I
decided the engine was running well for a test flight. I set the high speed
needle valve to a slight rich setting and took off. The engine acelerated weel
on the take off, but after a few turns on the sky and a cuban eigth with
reduced throtle on the dives the engine wouldn't accelerate imediately
and sounded lean. In these ocasions I backed the throtle and acelerated
again with no problems, but now the engine took more time to reach full speed
and sounded richer than the set up made on the ground. My
experience with YS engines refers to a 120 AC that ran beautifully rigth out
of the box, with adjustments made only on the high speed needle valve as these
engine doesn't have a low speed needle valve. I'm using an OS F glow plug and
Wildcat fuel with 10% nitro/ 18% oil. If anyone can help me with commentes,
specially for the slow speed neddle valve that doesn't seems to affect the way
the engine works, or even a personal setting for the engine I'll be
more than glad. I almost forgot to mention that I recently installed the same
engine in a GP U Can Do 3D with another fuel tank, fuel lines and YS Check
Valve. The problem persists.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks in advance,</FONT></DIV>
<DIV><FONT face=Arial size=2>Fausto -
Brazil</FONT></DIV></BLOCKQUOTE></BODY></HTML>