Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Mon, 06 Sep 2004 13:40:57 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d22.mx.aol.com ([205.188.144.208] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 395009 for lml@lancaironline.net; Mon, 06 Sep 2004 08:59:16 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.208; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d22.mx.aol.com (mail_out_v37_r3.4.) id q.158.3e64bdf4 (4320) for ; Mon, 6 Sep 2004 08:58:30 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <158.3e64bdf4.2e6db8f6@aol.com> X-Original-Date: Mon, 6 Sep 2004 08:58:30 EDT Subject: Re: [LML] Lycoming 320 X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1094475510" X-Mailer: 9.0 for Windows sub 5000 -------------------------------1094475510 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 9/5/2004 8:05:45 PM Central Standard Time, bobjude@charter.net writes: Does anyone on the lost have any experience with Lycoming engines backfiring or making a popping noise while taxiing? My Lyc 320 just started this strange behavior. Only when the engine is warmed up. The Pops are not continuous, only random and intermittent. I tried adjusting the idle mixture to a leaner setting. That didn't seem to help. Any suggestions would be appreciated. Bob, My understanding is that "popping" is caused by unburned fuel being ignited in the exhaust pipe. There are many possible reasons for this. Some might be bad timing, fouled plug, exhaust valve problem, peculiar fuel distribution caused by vaporization problems, etc. If the ignition system has an intermittant sparking problem, the exhaust pipe could be hot enough from prior correct combustion events to ignite unburned fuel from a missed ignition event not noticed at higher rpm. I guess I would check the plugs first, timing, hot compression check, then maybe consider the magneto points (may be due for an overhaul). Scott Krueger AKA Grayhawk Sky2high@aol.com II-P N92EX IO320 Aurora, IL (KARR) Opinions and results may vary! -------------------------------1094475510 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 9/5/2004 8:05:45 PM Central Standard Time,=20 bobjude@charter.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Does=20 anyone on the lost have any experience with Lycoming engines backfiringor=20 making a popping noise while taxiing?

My Lyc 320 just started this=20 strange behavior.  Only when the engine is
warmed up.  The Po= ps=20 are not continuous, only random and intermittent.

I tried adjusting= the=20 idle mixture to a leaner setting.  That didn't seem to
help. = Any=20 suggestions would be appreciated.
Bob,
 
My understanding is that "popping" is caused by unburned fuel being ign= ited=20 in the exhaust pipe.  There are many possible reasons for this.&nb= sp;=20 Some might be bad timing, fouled plug, exhaust valve problem, peculiar fuel=20 distribution caused by vaporization problems, etc.  
 
If the ignition system has an intermittant sparking problem, the exhaus= t=20 pipe could be hot enough from prior correct combustion events to ignite unbu= rned=20 fuel from a missed ignition event not noticed at higher rpm.
 
I guess I would check the plugs first, timing, hot compression che= ck,=20 then maybe consider the magneto points (may be due for an overhaul).=20
 
Scott Krueger=20 AKA Grayhawk
Sky2high@aol.com
II-P N92EX IO320 Aurora, IL=20 (KARR)

Opinions and results may=20 vary!
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