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<DIV><FONT face=Arial size=2>Michael,</FONT></DIV>
<DIV><FONT face=Arial
size=2>
The big and first thing to remember is that the DZ uses a pump. If you keep
thinking about the pump as a regulator it may not help you set your engine.
Unfortunately the instructions call it a regulator. The fuel is metered out
to the carb by the pushrod action and the "pulsating" crankcase pressure
operates the pump side.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The next thing is that the carb does two things. It
controls the air flow to the inlet valve and the fuel supply to the
injector. Even though the needle effects all of the fuel flow it is not the
right thing to use to get a good idle. Many people accidentally/unintentionally
override the pump settings with the main needle to get a good low-end
rpm.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The "regulator" screw restricts the primary fuel
flow and is the one that you must use to set an idle and transition. If you get
the big brass screw set a bit too rich it will keep dousing the plug,
especially at low rpm.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The trick to a good setting is to keep closing
the pumped fuel supply until the engine will not run any more.
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>You do this by turning the big brass
screw clockwise about 1/8 of a turn and then start and warm
up the engine. Keep the main needle at about 1.5 turns or more
and don't worry if it runs a bit rich as you open the throttle about
half way, in short bursts. Do this again and again until the engine will
not start or keep running at idle or open up.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>You are now very close. Turn the brass screw back
anti-clockwise about 1/8 of turn. and see if the engine will start and
idle. It should be able to go as low as, and hold about, 1.500 rpm.for about a
minute. If the throttle smoothly increases the rpm you have a good low-end
setting. (Go more "open" on the brass screw if it is needed to keep it
running).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Now is the time set your top-end needle. It may
need more or less fuel so please open up carefully and listen for the warning
"bark". Richen the main needle if it barks. If all goes well, set the
high-end needle for max rpm and then richen it back about 500 rpm.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>After that it should run like a Swiss-watch,
start better, and last a good while. It should not quit in the air or on the
ground.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Please let me know if this worked for
you.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Eric.</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=precisionaero@comcast.net
href="mailto:precisionaero@comcast.net">Michael Cohen</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, July 30, 2006 2:31 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] YS140DZ idle
question</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=3>OK list, I have a question for you. I have
a 140DZ that will not idle below 2300ish RPM. Richard Lindberg and I
have adjusted the regulator, but it appears to have little or no effect.
I might be able to get one flight in, but eventually, on a down line, it will
die and 7 dead sticks are not that fun to try. Full power seems to
hold just fine. We figured there might be an air leak, and that is why
it seemed to idle worse after a warm up flight, so I replaced the valve cover
gasket and the other gaskets at the backplate, but that did not seam to make a
difference. Anybody got any ideas besides the usual
OS/Webra/Mintor/E-power/power slope soaring comments?</FONT></DIV>
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