Return-Path: Received: from tomcat.al.noaa.gov ([140.172.240.2] verified) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3143242 for flyrotary@lancaironline.net; Fri, 02 Apr 2004 22:07:08 -0500 Received: from PILEUS.al.noaa.gov (pileus.al.noaa.gov [140.172.241.195]) by tomcat.al.noaa.gov (8.12.0/8.12.0) with ESMTP id i33377Ka027307 for ; Fri, 2 Apr 2004 20:07:07 -0700 (MST) Message-Id: <5.2.1.1.0.20040402200032.05cb7010@mailsrvr.al.noaa.gov> X-Sender: bdube@mailsrvr.al.noaa.gov X-Mailer: QUALCOMM Windows Eudora Version 5.2.1 Date: Fri, 02 Apr 2004 20:06:14 -0700 To: "Rotary motors in aircraft" From: Bill Dube Subject: Re: [FlyRotary] Re: Rusty's O2 / EM2 problems. In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed At 06:40 AM 4/1/2004 -0600, you wrote: >Greetings, > >I haven't had a chance to do anything else with my O2 testing, but I've >had an odd thought. > >The full story, is that I originally had erratic O2 readings with the >rev-2 configuration. Primarily, this was staying on the mid, to low end >of the scale, but would then just go away completely, as if it was way too >lean. I don't know if this will help, but I thought I would mention it anyway. When the engine is running at high manifold pressure, fuel will coat the manifold walls (after the fuel injectors.) When you shut the throttle, the manifold pressure drops and the fuel coating the manifold evaporates, leading to a very rich mixture. Depending on the length and roughness of the manifold runners, this rich condition can last quite awhile with a shut throttle. The flow is very low so the fuel can take quite some time to clear out. Would this explain the behavior of your engine?