X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Wed, 15 Nov 2006 11:25:07 -0500 Message-ID: X-Original-Return-Path: Received: from [68.168.78.77] (HELO mta15.adelphia.net) by logan.com (CommuniGate Pro SMTP 5.1.2) with ESMTP id 1568024 for lml@lancaironline.net; Wed, 15 Nov 2006 08:33:26 -0500 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.77; envelope-from=glcasey@adelphia.net Received: from [70.32.170.45] by mta15.adelphia.net (InterMail vM.6.01.05.04 201-2131-123-105-20051025) with ESMTP id <20061115132152.WZYF25578.mta15.adelphia.net@[70.32.170.45]> for ; Wed, 15 Nov 2006 08:21:52 -0500 Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-9-606779708 X-Original-Message-Id: From: Gary Casey Subject: Re: Hot starts X-Original-Date: Wed, 15 Nov 2006 05:32:53 -0800 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.2) --Apple-Mail-9-606779708 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Mark said: I used to set the throttle wide open, as a number of other listers wrote, for a hot start. Some years ago, someone on the LML suggested a better or at least more conservative way. If you set the throttle only partially open - say one quarter travel - the air supply is far greater than the engine needs for cranking or idle. There is no advantage to going all the way wide open. The disadvantage of using full open throttle becomes apparent if you fumble the controls at all. Maybe the start button should be foot operated so we can keep one hand on the throttle and the other on the mixture.....; ) Mark Ravinski You beat me to it, Mark. That's exactly right - once the throttle is more than just cracked it offers no restriction during cranking, so there is no advantage to opening the throttle fully during a hot start. I just open it only a touch more than for a cold start, and most of the reason is to make sure it keeps running once it fires. There will often be vapor in the system that has to get purged, so the engine will sometimes misfire and surge for a bit after starting. As Mark says, with the throttle wide open a slip of the hand after it starts will result in an unexpected full throttle run- up at the gas pump. If you don't believe all this, just watch the manifold pressure during cranking - it will barely flicker off barometric pressure, even with the throttle fully closed. I think the wide open throttle legend got started with carburetors in cars and Cubs, which are likely to pull in fuel when at idle position. The full throttle had nothing to do with getting more air and all to do with making sure the carb didn't allow fuel into the engine. Gary Casey --Apple-Mail-9-606779708 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1

Mark = said:

I used to set the = throttle wide open, as a number of other listers wrote, for a hot = start.

Some years ago, = someone on the LML suggested a better or at least more conservative = way.

If you set the = throttle only partially open - say one quarter travel - the air supply = is far greater than the engine needs for cranking or idle.=A0 There is = no advantage to going all the way wide open.

The disadvantage of using full open throttle becomes apparent if = you fumble the controls at all.

=A0

Maybe the start = button should be foot operated so we can keep one hand on the throttle = and the other on the mixture.....; )

=A0

Mark = Ravinski

You beat me to it, Mark.=A0 That's exactly right - = once the throttle is more than just cracked it offers no restriction = during cranking, so there is no advantage to opening the throttle fully = during a hot start.=A0 I just open it only a touch more than for a cold = start, and most of the reason is to make sure it keeps running once it = fires.=A0 There will often be vapor in the system that has to get = purged, so the engine will sometimes misfire and surge for a bit after = starting.=A0 As Mark says, with the throttle wide open a slip of the = hand after it starts will result in an unexpected full throttle run-up = at the gas pump. =A0If you don't believe all this, just watch the = manifold pressure during cranking - it will barely flicker off = barometric pressure, even with the throttle fully closed. =A0I think the = wide open throttle legend got started with carburetors in cars and Cubs, = which are likely to pull in fuel when at idle position. =A0The full = throttle had nothing to do with getting more air and all to do with = making sure the carb didn't allow fuel into the engine.

Gary = Casey=A0=A0

= --Apple-Mail-9-606779708--