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<HTML><HEAD><TITLE>Re: YS 61 Long Stroke "need more help"</TITLE>
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<DIV><FONT face=Arial size=2>I would check the piston ring gap. This was a
proble I had with my 120 AC. Also check the cam gear timing. For
some reason some of the AC had a problem with jumping out of time.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ron</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=xavier.mouraux@sympatico.ca
href="mailto:xavier.mouraux@sympatico.ca">Xavier Mouraux</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> Wednesday, October 29, 2003 10:17
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> YS120AC not running</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hello guys,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I have a problem with my 120AC and I didn't found
the solution in old messages from the list so I need help.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I have been flying that engine for almost 3 years
now, first in a Nova and this year in a Hydeout. It has been reliable for 2
1/2 years. Then, the day before the Oakville contest, it lost power and
RPM (down to 6500 from 8300 on a 15x12 on 30%). Checking the engine didn't
show anything obvious. However, we changed all the seals
and O-ring, repolish the back plate (small mark on it) and
rotary valve, clean the valves, clean the carburetor, check the piston
and lining, etc. We didn't remove the cam but could see that it looks
in good shape. After reassembly, the engine runs better than ever
(8500 with the 15x12 and 30%). It run fine for 2 months and about 50 flights
with regular valve checking.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>A few weeks ago, it begin being difficult to
start and wasn't getting normal RPM after a minute of running on the ground
during range check. There was smoke on the exhaust that looks as usual.
Checking the engine from the outside again didn't show anything obvious but it
didn't even start anymore. I opened it last week and clean the valves (some
carbon on it), repolish the backplate (a little mark on it). It still doesn't
start. New plug was tried, different glow drivers, turn the plane upside down,
remove the needle valve, check the pressure (seems normal - a few turn of the
prop by hand get pressure in the system), compression seems good. I
haven't disassemble the air chamber but will do it tomorrow
night. Maybe I will dismantle the carb also.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>What else could I check or try ?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I would like to fly it a few more time before the
snow arrive here in a few weeks :-) </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks in advanced</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Xavier</FONT></DIV></BLOCKQUOTE></BODY></HTML>