X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 27 Dec 2012 18:26:07 -0500 Message-ID: X-Original-Return-Path: Received: from imr-da06.mx.aol.com ([205.188.169.203] verified) by logan.com (CommuniGate Pro SMTP 6.0) with ESMTP id 5970897 for lml@lancaironline.net; Thu, 27 Dec 2012 13:38:05 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.169.203; envelope-from=Sky2high@aol.com Received: from mtaomg-mb05.r1000.mx.aol.com (mtaomg-mb05.r1000.mx.aol.com [172.29.41.76]) by imr-da06.mx.aol.com (Outbound Mail Relay) with ESMTP id E0F6B1C000158 for ; Thu, 27 Dec 2012 13:37:29 -0500 (EST) Received: from core-mta001b.r1000.mail.aol.com (core-mta001.r1000.mail.aol.com [172.29.234.129]) by mtaomg-mb05.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 9FA5AE00008B for ; Thu, 27 Dec 2012 13:37:29 -0500 (EST) From: Sky2high@aol.com Full-name: Sky2high X-Original-Message-ID: X-Original-Date: Thu, 27 Dec 2012 13:37:28 -0500 (EST) Subject: Re: [LML] Re: Mixture adjustment X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_db09.51cce2a5.3e0def68_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:462865248:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d294c50dc956964b3 --part1_db09.51cce2a5.3e0def68_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit An additional point - If an electronic ignition is used, it is important to properly set the idle lean mixture and it will always be leaner than the same engine using ordinary magnetos. Because idle and taxi power is so low (low rpm, low map), the spark is advanced quite a bit, sometimes to about 34 DBTDC. I have a dual Plasma III system and after an engine start I always lean the mixture and see a rise in rpm. The mixture remains leaned during taxi and run up checks (1800-1900 rpm) as this is a greater stress on ignition components - there is no engine stumbling and shutting off one of the ignitions only results in a drop of 10-20 rpm. Grayhawk IO 320 In a message dated 12/27/2012 8:54:40 A.M. Central Standard Time, casey.gary@yahoo.com writes: I agree with Walter. The only problem with being a little on the lean side (as yours apparently is) is that when cold the engine might not keep running if brought back to an idle, and it may stumble if the throttle is opened abruptly from idle when cold. The problem with being rich (the 25-5-0 rpm drop is pretty rich) is that when operating at a high-elevation airport if you don't lean it aggressively at idle it can quit. Like on roll-out after landing. BTDT. Regardless, it only affects operation on the ground. If it is running good, I wouldn't bother changing it. Gary Casey The 25-50 RPM rise should be seen at sea level. What's your home airport elevation? (I prefer to have it on the lean side.) Walter Atkinson Advanced Pilot Seminars On Dec 26, 2012, at 6:23 AM, Greenbacks, UnLtd. wrote: My IO360 idles smoothly at 760-780RPM. I've been told that the correct mixture setting at idle has been achieved when pulling mixture to full lean results in a 25-50RPM increase before the engine quits. Is this what I should be looking for? I don't see it yet so I'm thinking I should richen up the mixture a click or two until I see the rise. What do our resident engine experts say? Thanks, Angier Ames N4ZQ --part1_db09.51cce2a5.3e0def68_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
An additional point - If an electronic ignition is used, it is importa= nt to=20 properly set the idle lean mixture and it will always be leaner than t= he=20 same engine using ordinary magnetos.  Because idle and taxi power= is=20 so low (low rpm, low map), the spark is advanced quite a bit, sometime= s to=20 about 34 DBTDC.  I have a dual Plasma III system and=20 after an engine start I always lean the mixture and see a ri= se in=20 rpm.  The mixture remains leaned during taxi and run up checks (1800-1= 900=20 rpm) as this is a greater stress on ignition components - there is=20 no engine stumbling and shutting off one of the ignitions only results= in a=20 drop of 10-20 rpm.
 
Grayhawk
IO 320  
 
In a message dated 12/27/2012 8:54:40 A.M. Central Standard Time,=20 casey.gary@yahoo.com writes:
=
I agree with Walter.  The only problem with being a little on t= he=20 lean side (as yours apparently is) is that when cold the engine might not= keep=20 running if brought back to an idle, and it may stumble if the throttle is= =20 opened abruptly from idle when cold.  The problem with being rich (t= he=20 25-5-0 rpm drop is pretty rich) is that when operating at a high-elevatio= n=20 airport if you don't lean it aggressively at idle it can quit.= =20  Like on roll-out after landing.  BTDT.  Regardless, it on= ly=20 affects operation on the ground.  If it is running good, I wouldn't= =20 bother changing it.
Gary Casey 

The=20 25-50 RPM rise should be seen at sea level.  What's your home airpor= t=20 elevation?

(I prefer to have it on the lean side.)

Walter= =20 Atkinson
Advanced Pilot Seminars



On Dec 26, 2012, at 6:= 23=20 AM, Greenbacks, UnLtd. wrote:

My IO360 idles smoothly at=20 760-780RPM.
I've been told that the correct mixture setting at idle ha= s=20 been achieved when pulling mixture to full lean
results in a 25-50RPM= =20 increase before the engine quits. Is this what I should be looking for?I=20 don't see it yet so I'm thinking I should richen up the mixture a click o= r two=20 until I see the rise.
What do our resident engine experts=20 say?

Thanks,

Angier=20 Ames
N4ZQ
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