---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Sun 01/15/12: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:59 AM - Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Thruster87) 2. 01:30 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (James, Clive R) 3. 02:01 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Martin Hone) 4. 02:02 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Martin Hone) 5. 02:46 PM - Re: Bing 64 Idle circuit inlet aperture drilling 3300A (dons701) ________________________________ Message 1 _____________________________________ Time: 12:59:18 AM PST US Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A From: "Thruster87" [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air bleed at the intake bellmouth or the fuel jet in the float bowl that feeds the starting jet(choke) ? Yes it was at the bellmouth [small brass orifice intake side bottom].Turning the mixture screw further clockwise,wouldn't that just lean out the mixture thus also increasing the temps and with the surging problem it feels like it's not getting enough fuel? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=363814#363814 ________________________________ Message 2 _____________________________________ Time: 01:30:43 AM PST US Subject: RE: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A From: "James, Clive R" Can you not set the idle mixture with the engine running? You can find the spread of screw position where it will run smoothly (rich to lean and back to rich) and then try either end to see what's best when flying. Certainly a strange one. Regards, Clive -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Thruster87 Sent: 15 January 2012 08:57 Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A --> [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air bleed at the intake bellmouth or the fuel jet in the float bowl that feeds the starting jet(choke) ? Yes it was at the bellmouth [small brass orifice intake side bottom].Turning the mixture screw further clockwise,wouldn't that just lean out the mixture thus also increasing the temps and with the surging problem it feels like it's not getting enough fuel? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=363814#363814 ________________________________ Message 3 _____________________________________ Time: 02:01:12 AM PST US Subject: Re: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A From: Martin Hone There are two airbleeds if I remember correctly. One is the idle air bleed on the LH side of the bellmouth, and the centre one feeds the emulsion tube and needle jet ( this can also be drilled - to 3/16"). Turning clockwise will reduce fuel flow and thereby lean the mixture. That's why I suggested at least 2 turns out ( counterclockwise). On a stock set-up, the idle mixture screw has minimal effect. Drilling out the airbleed helps. Going to the next size richer idle jet (pilot jet) can help as well ( from say #35 to #40 ) Marty On Sun, Jan 15, 2012 at 6:56 PM, Thruster87 wrote: > alania@optusnet.com.au> > > [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air > bleed at the intake bellmouth or the fuel jet in the float bowl that feeds > the starting jet(choke) ? > > Yes it was at the bellmouth [small brass orifice intake side > bottom].Turning the mixture screw further clockwise,wouldn't that just lean > out the mixture thus also increasing the temps and with the surging problem > it feels like it's not getting enough fuel? > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=363814#363814 > > ________________________________ Message 4 _____________________________________ Time: 02:02:13 AM PST US Subject: Re: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A From: Martin Hone Have you checked the actual pilot jet ? It is possible that it may simply be obstructed . Not uncommon to find it blocked or partially restricted. Marty On Sun, Jan 15, 2012 at 7:27 PM, James, Clive R wrote: > clive.james@uk.bp.com> > > Can you not set the idle mixture with the engine running? > You can find the spread of screw position where it will run smoothly (rich > to lean and back to rich) and then try either end to see what's best when > flying. > > Certainly a strange one. > > Regards, Clive > > -----Original Message----- > From: owner-jabiruengine-list-server@matronics.com [mailto: > owner-jabiruengine-list-server@matronics.com] On Behalf Of Thruster87 > Sent: 15 January 2012 08:57 > To: jabiruengine-list@matronics.com > Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture > drilling 3300A > > --> > > [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air > bleed at the intake bellmouth or the fuel jet in the float bowl that feeds > the starting jet(choke) ? > > Yes it was at the bellmouth [small brass orifice intake side > bottom].Turning the mixture screw further clockwise,wouldn't that just lean > out the mixture thus also increasing the temps and with the surging problem > it feels like it's not getting enough fuel? > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=363814#363814 > > ________________________________ Message 5 _____________________________________ Time: 02:46:08 PM PST US Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A From: "dons701" Hi The idle air bleed needs to be drilled to 1.6mm or, .0629, or a 1/16" drill bit will do. As others have said, turning out is "rich" in "lean". The idle mixture screw is essentially an adjustable throttle because it controls the volume of the emulsion of air from the air bleed AND fuel from the idle jet. What determines rich or lean in the end is actually the relationship between airflow from the clearance around the throttle blade and the volume of air and fuel coming from the idle port located just downstream of the throttle blade. Oddly your troubles seem to start when preparing to land. Besides reduction of throttle to 2000 rpm, what else is done? Do you turn on the fuel pump? Carb heat? What is the fuel pressure at this moment? My ultimate guess is that the engine is at the rich limit such that when pulled to idle the "fire goes out". What are your exhaust temps at full throttle and cruise? .......DonB -------- Zenith 701 #76120 Jabiru 2200A #2456 95 hours Sensenich Wood 64-PJ-36 Prop Read this topic online here: http://forums.matronics.com/viewtopic.php?p=363908#363908 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.