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<DIV><FONT face=Arial size=2>If it has been back for service then the problem is
inside the model.</FONT></DIV>
<DIV><FONT face=Arial size=2>Richard runs them all on a test stand before they
leave his shop. He makes sure that they work and are all setup.....</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>SO .......next step....</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Motor Mount loose?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Throttle servo bad? crappy throttle servos are a
common occurrence. The thinking is well its the go handle....all it has to do is
move the throttle works. Well many cheapy servo are not very good at holding
position and enter the vibration that might be involved especially at
idle....Well they will jump around.</FONT></DIV>
<DIV><FONT face=Arial size=2>I tend to use a very good servo on the
throttle....</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Idle just too low? should be 2000 or maybe
2100-2200...not 1600-1800</FONT></DIV>
<DIV><FONT face=Arial size=2>Fuel used? Many times the low nitro fuel like 10 or
15% will have inconsistent idle this is why you should use at least 20%
Nitro</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Tank problems or maybe a fuel filter that is
leaking or partially clogged up....Under full power sometimes a clogged or
restricted fuel filter will not show up as easily as its got such a high flow
rate...at idle the flow rate is less and sometimes a partial clog in the
filter...same thing for leaks.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Plug? OS #F or YS plug...and its in good shape?
Maybe trade it out.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If all this doesn't help then try some leak free
gaskets to stop any leaks if there are any...my guess is no because Richard
would have replaced any gaskets.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Troy Newman</FONT></DIV>
<BLOCKQUOTE
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=billglaze@triad.rr.com href="mailto:billglaze@triad.rr.com">Bill
Glaze</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> Thursday, January 29, 2004 10:20
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: YS FZ91 Problem</DIV>
<DIV><BR></DIV>He stated that it's been back to Richard already; they haven't
fixed the problem.<BR>Have they run the engine on a test stand? Sometimes that
can be very instructive. I know that the engine works well on the
ground, only problem being at idle for landing. How does it take
prolonged idle in the air if landing isn't intended? Frequently, the
longest period of time the engine is at idle, is in the landing setup and
landing pattern. What kind of RPM's is the engine set for at
idle?<BR><BR>Bill Glaze<BR><BR>Troy Newman wrote:<BR>
<BLOCKQUOTE cite=midBAY4-DAV1515unJop4l0005f72a@hotmail.com type="cite"><PRE wrap="">If its a new motor send to YS Performance. Richard and crew will fix it up
right as rain....it will only cost you the $5 for shipping to him.
Especially if its a warranty thing.
TN
----- Original Message -----
From: "Ed White" <A class=moz-txt-link-rfc2396E href="mailto:edvwhite@yahoo.com"><edvwhite@yahoo.com></A>
To: <A class=moz-txt-link-rfc2396E href="mailto:discussion@nsrca.org"><discussion@nsrca.org></A>
Sent: Wednesday, January 28, 2004 10:11 PM
Subject: YS FZ91 Problem
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">Folks,
We have a club member who is really interested in
pattern and bought a ARF pattern plane and put a YS
FZ91 in it to fly Sportsman and Intermediate. The YS
has been a problem since he bought it. It starts
easily and runs great on the ground, idles beautifully
before take-off, has good power in the air and flys
the intermediate sequence well. Then he sets up for
landing and on the downwind or base leg the engine
quits. I don't mean occasionally quits, I mean every
stinking time.
This is a very low time engine and the only time I've
seen it land under power was when the throttle linkage
slipped and he couldn't make it idle. We've checked
for pressure leaks, run the same magnum fuel I use in
my FZ140, tried the idle leaner, tried the idle
richer. He sent the engine back to YS who installed
an "updated" piston. All to no avail.
I finally got him to give me the engine to tear down
and look at. I haven't got very far into it, just
pulled the valve and airbox covers and diaphragm. I
was sorta hoping to find an air leak but so far
nothing obvious. Any thoughts/experience from the
community?
Thanks,
Ed
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