Return-Path: Sender: (Marvin Kaye) To: lml Date: Thu, 03 Apr 2003 20:53:30 -0500 Message-ID: X-Original-Return-Path: Received: from [64.8.50.205] (HELO mta11.adelphia.net) by logan.com (CommuniGate Pro SMTP 4.1b2) with ESMTP id 2101585 for lml@lancaironline.net; Wed, 02 Apr 2003 08:41:28 -0500 Received: from worldwinds ([207.175.254.66]) by mta11.adelphia.net (InterMail vM.5.01.05.32 201-253-122-126-132-20030307) with SMTP id <20030402134127.FKRR10225.mta11.adelphia.net@worldwinds> for ; Wed, 2 Apr 2003 08:41:27 -0500 From: "Gary Casey" X-Original-To: "lancair list" Subject: RE: [LML] IO-320 / Hartzell Prop Strange RPM Behavior (Long) X-Original-Date: Wed, 2 Apr 2003 05:37:32 -0800 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 There have been lots of other guesses, so here's mine: Is there something wrong with the front main bearing where the engine oil pressure is getting into the prop control. Like a spun bearing? Then the governor would reduce the pressure until it got lower than the engine oil pressure at which time it can't go any lower, holding the prop at a pitch higher than the mechanical stop allows. I don't like my idea as it is expensive, but it might be a logical explanation. Could put a pressure gage on the prop governor line if it is a rear-mounted governor. Adjusting the oil pressure down would then help, not hurt the problem. Try adjusting it down to maybe 50 psi for a test? Gary Casey