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<DIV>All,</DIV>
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<DIV>It is evident that I had been setting the low end lean. Next time I fly, I will adjust to get richer low end. I don't think I am running the engine hot. However, I am going to try to improve cooling and see if this helps. </DIV>
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<DIV>Thanks to all again. I got very good feedback. </DIV>
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<DIV>Vicente Bortone</DIV>
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<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message -------------- <BR>From: "John Pavlick" <jpavlick@idseng.com> <BR><BR>> Jerry, <BR>> Thanks for confirming my observation re- lean idle = slow transition to <BR>> idle. I first noticed this on my old Arctic Cat sleds. I've always felt more <BR>> comfortable with 4-strokes - I guess that comes from wrenching Harleys. I'm <BR>> finally figuring these ringy-dingy 2-strokes out I guess. So who says toy <BR>> airplanes aren't educational? <BR>> <BR>> John Pavlick <BR>> http://www.idseng.com <BR>> <BR>> BTW - I've been using sealed bearings (seals on both sides / -2RS type) <BR>> front and rear. In stock configuration, normally the front bearing is <BR>> shielded on one side only - no seals. This does nothing (or at best very <BR>> little) to seal the crankcase. With both sides sealed, there is much less <BR>> chance of an air leak that would definitely causes slow transition AND <BR>> erratic idle. In extreme cases I've seen motors that wouldn't shut off even <BR>> with the throttle fully closed. The fix was new bearings. <BR>> <BR>> <BR>> <BR>> > -----Original Message----- <BR>> > From: nsrca-discussion-bounces@lists.nsrca.org <BR>> > [mailto:nsrca-discussion-bounces@lists.nsrca.org]On Behalf Of Jerry Budd <BR>> > Sent: Tuesday, March 07, 2006 12:28 AM <BR>> > To: NSRCA Mailing List <BR>> > Subject: Re: [NSRCA-discussion] Fuel Regulation in 2C Engines <BR>> > <BR>> > <BR>> > >5. It is clear that all 2-cycle engines will have this behavior. <BR>> > <BR>> > I guess I have to offer a different opinion on this. If you have the <BR>> > low end set lean (and most running the OS140Rx are running the bottom <BR>> > lean to get the mid-range somewhat reasonable) you will not be able <BR>> > to get the motor to settle into a low idle quickly. And that <BR>&g
t; > presents itself as poor down line breaking, as well as the occasional <BR>> > flameout. When I ran the OS140's I bought four motors and then <BR>> > picked the two with the best carbs (aka midrange) so I could set the <BR>> > low end where it belonged. I also used higher nitro fuel (Magnum #1) <BR>> > to help lean the midrange, which also allowed me to run the pipe <BR>> > about an inch longer (which helped soften the pipe "bump"). <BR>> > <BR>> > I had good luck (post '02 Nats) and good power (8400 rpm, APC 17x12) <BR>> > with the OS's, but I found that the throttle response wasn't the best <BR>> > if you used a lot of throttle to control speed. When I switched to <BR>> > the Webra 160 I was able to set the top end rich and still have more <BR>> > power than I knew what to do with (because of the enormous <BR>> > torque/very conservative exhaust timing), and also set the idle <BR>> > slightly rich so the motor would quickly settle into a low stable <BR>> > idle. Of course this was a lot easier to do with the MC carb since I <BR>> > didn't have to compromise on the mixture settings. <BR>> > <BR>> > But, anyway, to bring this back to point. The most prevalent reason <BR>> > for a 2c to have an erratic idle with poor down line braking is a too <BR>> > lean idle and a hot motor (like Evil Eric said). Adding a fuel pump <BR>> > or a pressure regulator or whatever won't fix that. <BR>> > <BR>> > Just my $0.02 worth, <BR>> > <BR>> > Jerry <BR>> > -- <BR>> > ___________ <BR>> > Jerry Budd <BR>> > Budd Engineering <BR>> > (661) 722-5669 Voice/Fax <BR>> > (661) 435-0358 Cell Phone <BR>> > mailto:jerry@buddengineering.com <BR>> > http://www.buddengineering.com <BR>> > _______________________________________________ <BR>> > NSRCA-discussion mailing list <BR>> > NSRCA-discussion@lists.nsrca.org <BR>> > h
ttp://lists.nsrca.org/mailman/listinfo/nsrca-discussion <BR>> > -- <BR>> > No virus found in this incoming message. <BR>> > Checked by AVG Free Edition. <BR>> > Version: 7.1.375 / Virus Database: 268.2.0/275 - Release Date: 3/6/06 <BR>> > <BR>> -- <BR>> No virus found in this outgoing message. <BR>> Checked by AVG Free Edition. <BR>> Version: 7.1.375 / Virus Database: 268.2.0/275 - Release Date: 3/6/06 <BR>> <BR>> _______________________________________________ <BR>> NSRCA-discussion mailing list <BR>> NSRCA-discussion@lists.nsrca.org <BR>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion </BLOCKQUOTE></body></html>