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<DIV><FONT face=Arial size=2>Keith, Matt, I have not messed with the pump yet
but that is next, I had lots of mail that said don't mess with the pump and a
few that said it's ok. I have triple checked everything else and adjusted
needles 1/16 at a time from one extream to the other, I guess adjusting the
pump is in order. Is everyone in agrement that increasing the spring pressure in
the pump increases the pressure.</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=tkeithb@attbi.com href="mailto:tkeithb@attbi.com">Keith Black</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, June 05, 2003 6:56
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: MC carb for Webra</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Brian, have you experimented with increasing the
pump pressure? Maybe the upline mid-range is starving due to not having enough
fuel but WOT creates enough extra suction to pull the fuel through.
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you haven't already tried this why don't you
increase the pump pressure by 1/4 turn at a time and see if it
helps.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>BTW, you're correct that the throttle is very
non-linear. Once my carb is about half open the engine is much closer to full
throttle than mid throttle. I added a mix to my radio to introduce an expo
behavior with the throttle and this tremendously improved how linear the
throttle response is on my throttle stick. This made the plane much easier to
fly.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Good luck,</FONT></DIV>
<DIV><FONT face=Arial size=2>Keith Black</FONT></DIV>
<DIV><FONT face=Arial size=2></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=auto7832@bellsouth.net href="mailto:auto7832@bellsouth.net">Brian
Billings</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, June 05, 2003 2:27
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> MC carb for Webra</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2> Bob, I was very careful
running this motor in, ran several tanks through engine before flying and
monitored the cylinder head temp the whole time. Motor ran great the first
weekend out with the plane but the next weekend motor was having trouble
from the first start of the day and I was unable to fly due to
troubles, sagging mainly. I sent motor to piedmont for check out and they
said it ran fine and had no problems. I can hold engine against compression
with no leak down felt but the discoloration of the ring and top of piston
does add credence to your theory, plus it does seem like there is less
compression once engine has been ran to operating temperature. I would put a
piston, ring and liner in it if I new my problems would go away but I am
afraid that it is not the root of my problem but a outcome of the sagging in
flight. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><BR><FONT face=Arial><FONT size=2>Hi<BR><BR>I'm sticking my nose in
here, but I've been running the Greve (Piedmont) set up for some time now
and at their setting it WORKS, very well. I agree with Jerry, by the
way, the numbers are wrong, based on my theory, but it works so I have not
messed with it. Reading your symptoms, I suspect you have a bad ring,
allowing blow by into the crank case, which changes with temp, which changes
the crank case pressure, which changes the "pump performance", which changes
the temp, which changes........ I have found that long before the ring
is worn enough to cause loss of compression/power it will upset the
pump/regulator (speaking of the OS here) because of combustion blow by into
the crankcase. Not enough leakage to effect peak performance, but with
crankcase pressure at 8-12 lbs (I think those are the numbers) and
combustion pressure at probably thousands of lbs a little leakage
could double the case pressure and screw things up. I have found
replacing the ring sometimes ring and cylinder to solve this, anyway, the
theory as to way is just that, theory/speculation.<BR><BR>Hope this
helps<BR><BR>Bob</FONT> </FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>