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<DIV><SPAN class=220402504-29042006><FONT face=Arial color=#0000ff
size=2>Colin,</FONT></SPAN></DIV>
<DIV><SPAN class=220402504-29042006><FONT face=Arial color=#0000ff
size=2> When you replaced the bearing did you notice how the ring was
installed on the piston? I know this causes problems on the OS160 - there is a
<EM>very</EM> small alignment pin in the piston ring groove that locates the end
of the ring. The ring needs to be indexed so that it aligns properly with the
ports. It's possible to put the engine back together with the ring
misaligned if you're not careful and this would distort the ring badly enough to
make the engine run poorly. Believe me, I've seen guys do it. I would carefully
disassemble the engine again, noting the position of the ring. At this point it
probably wouldn't hurt to just replace the ring + sleeve anyway. I don't know
how long they last on a 140 - maybe someone else can answer that. I had the same
sort of problem with an old 46 SF - very similar symptoms to what you're
describing. Turned out to be a ring + sleeve. Engine is as good as new
now.</FONT></SPAN></DIV>
<DIV><SPAN class=220402504-29042006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=220402504-29042006>
<P><FONT size=2>John Pavlick<BR><A href="http://www.idseng.com/"
target=_blank>http://www.idseng.com</A><BR> </FONT> </P></SPAN></DIV>
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style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of </B>colin
chariandy<BR><B>Sent:</B> Saturday, April 29, 2006 12:13 AM<BR><B>To:</B>
NSRCA Mailing List<BR><B>Subject:</B> [NSRCA-discussion] OS140rx problems -
help needed.<BR><BR></FONT></DIV>
<DIV>Hello </DIV>
<DIV> </DIV>
<DIV>I started having problems with my 200-300flight old rx last season after
I lost my muffler ( Bolly 460) in flight. I decided to upgrade from
a muffler to an Aeroslave pipe. The motor ran poorly on the pipe and I
blamed the set-up. Poor midrange required that I back out the pump 3/4 and set
the top end a bit lean for reliable operation in the air. The setting would
change from one flight to the next. On the ground the engine
would load up and eventually quit 1/2 the time. I have now gone back to a
muffler ( Bolly 590) and the engines runs exactly the same as on the
pipe...very poor mid-range, erratic operation.</DIV>
<DIV> </DIV>
<DIV>Previous bearing replacement was the stock item put in 50 flights before
the problems started.</DIV>
<DIV> </DIV>
<DIV>I'm going to guess I need to replace the main bearing. What should I buy
and where? What else should I check/replace ? When should ring/sleeve be
replaced? Does anything else go wrong with these engines...pump problems
?</DIV>
<DIV> </DIV>
<DIV>All inputs are welcome.</DIV>
<DIV>Colin.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<P>
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