X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta05-srv.windstream.net ([166.102.165.166] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2735829 for flyrotary@lancaironline.net; Mon, 18 Feb 2008 19:45:06 -0500 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.166; envelope-from=montyr2157@alltel.net Received: from ispmxaamta08-gx.windstream.net ([98.20.144.102]) by ispmxmta05-srv.windstream.net with ESMTP id <20080219004419.PPWX5911.ispmxmta05-srv.windstream.net@ispmxaamta08-gx.windstream.net> for ; Mon, 18 Feb 2008 18:44:19 -0600 Received: from Thorstwin ([98.20.144.102]) by ispmxaamta08-gx.windstream.net with SMTP id <20080219004418.XHOX27517.ispmxaamta08-gx.windstream.net@Thorstwin> for ; Mon, 18 Feb 2008 18:44:18 -0600 Message-ID: <000601c87290$8fb15600$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: staging Date: Mon, 18 Feb 2008 18:44:15 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0003_01C8725E.42E90980" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0003_01C8725E.42E90980 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Don, Hang in there. Based on what you say in your email, I would look very closely at fuel = delivery. If your pumps are squealing, they are sucking air, or you have = vapor lock. The fuel is what lubes and cools the pump. If there is no = fuel flowing they overheat. Check for pinched lines, clogged filters, = loose/bad fittings on the suction side. Also, just having the pump = uphill from the tanks as little a 12 in can cause this problem. You need = good gravity feed to the pump and an adequate low restriction line. = Pumps are good at pushing fuel, but terrible at sucking it. These = problems are more common with high volatility winter blends of fuel. Verify that there are no air bubbles in the pump discharge with a clear = line.=20 Bubbles in the line, of air, or fuel vapor will cause the engine to lean = out irregularly which will cause bucking, and stumbling. There is no way = you will be able to tune the motor if this is the problem.=20 EFI pumps work best in the tank or at least with gravity feeding fuel to = them.=20 Good luck, Monty ------=_NextPart_000_0003_01C8725E.42E90980 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Don,
 
Hang in there.
 
Based on what you say in your email, I = would look=20 very closely at fuel delivery. If your pumps are squealing, they = are=20 sucking air, or you have vapor lock. The fuel is what lubes and cools = the pump.=20 If there is no fuel flowing they overheat. Check for pinched lines, = clogged=20 filters, loose/bad fittings on the suction side. Also, just having the = pump=20 uphill from the tanks as little a 12 in can cause this problem. You = need=20 good gravity feed to the pump and an adequate low restriction = line. Pumps=20 are good at pushing fuel, but terrible at sucking it. These = problems are=20 more common with high volatility winter blends of = fuel.
 
Verify that there are no air bubbles in = the pump=20 discharge with a clear line.
 
Bubbles in the line, of air, or fuel = vapor will=20 cause the engine to lean out irregularly which will cause bucking, and=20 stumbling. There is no way you will be able to tune the motor if this is = the=20 problem.
 
EFI pumps work best in the tank or at = least with=20 gravity feeding fuel to them.
 
 
Good luck,
 
Monty
 
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