---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 05/11/09: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:58 AM - Re: 912 One cylinder running rich (K Dilks) 2. 04:34 AM - Re: 912 One cylinder running rich (Thom Riddle) 3. 08:28 AM - Fuel Line Growing (Jim Feldmann) 4. 09:01 AM - Re: Fuel Line Growing (lucien) 5. 09:52 AM - Re: Fuel Line Growing (Joe Ronco) ________________________________ Message 1 _____________________________________ Time: 12:58:44 AM PST US Subject: RotaxEngines-List: Re: 912 One cylinder running rich From: "K Dilks" If No1 cyl really runs rich at idle it can be the idle jet is getting blocked. I know this sounds wrong but bear with me. As Roger says the inlet manifold distributes the fuel not so well at low speeds but if the idle jet gets blocked cyl 1 runs rich from fuel being pulled by the high vacuum through the main jet, but this does not atomize well and goes to number 1 at idle. When fully block it will flood No1 and run on 3 cylinders. When the engine speeds up to about 2200 rpm the situation is reversed and cyl 3 get the rich mix. Blow out the small idle jet and check idle mixture screw is no more that 1 1/2 turns open. Hope this is clear Kev -------- Austria ............. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243504#243504 ________________________________ Message 2 _____________________________________ Time: 04:34:45 AM PST US Subject: RotaxEngines-List: Re: 912 One cylinder running rich From: "Thom Riddle" Pete, In addition to what others have said about unequal air/fuel distribution at low engine speed, there is one other possibility. This occurred on a 912UL in an Allegro 2000. It turned out to be a partially broken light gage wire in the ignition circuit. I can't tell you which wire it was but the insulation was white in color and it was very light gage, probably #18 or #20. Before we found the partially broken wire and repaired it, the plugs in #1 cylinder were always very sooty. There was no differential compression problem and no perceptible loss of power. After the repair, the front cylinder plugs were still darker than the rear cylinder plugs but not like before the repair. So if all else fails to cure the sooty front plugs, do an thorough examination of every inch of your ignition system wiring. You may find a partial break as I did. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix A complex system that works is invariably found to have evolved from a simple system that works. - John Gaule Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243510#243510 ________________________________ Message 3 _____________________________________ Time: 08:28:09 AM PST US Subject: RotaxEngines-List: Fuel Line Growing From: "Jim Feldmann" I just replaced all of the flexible fuel lines (wing tanks to header and firewall forward) with new Goodyear SAE 30R7 rubber fuel line. After a day or two I noticed that the lines seemed to have gotten longer, so I did a test. Immersing a 3" long piece of fuel line in fuel for 48 hours caused it to grow to 3 1/8" long. I put a piece of Gates SAE 30R7 in with it, and it grew by exactly the same amount. Fortunately, the ID increased as well, so I am not immediately concerned that it will restrict the fuel flow, but clearly, the fuel is infiltrating the rubber. The fuel I'm running right now is 50% 100LL, 50% 91 octane autogas and the appropriate amount of Decalin. There is no measurable ethanol in the mix. It's been warm here, so I did a control test to see if temperature would cause expansion and contraction. I put a second 3" sample of each brand in the refrigerator for 48 hours. No change in the length of either one. Has anyone experienced this. -------- Jim Feldmann, 3rd owner 1994 Kitfox IV Speedster / 912 Working on my Sport Pilot Certificate Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243542#243542 ________________________________ Message 4 _____________________________________ Time: 09:01:21 AM PST US Subject: RotaxEngines-List: Re: Fuel Line Growing From: "lucien" Jim Feldmann wrote: > I just replaced all of the flexible fuel lines (wing tanks to header and firewall forward) with new Goodyear SAE 30R7 rubber fuel line. After a day or two I noticed that the lines seemed to have gotten longer, so I did a test. > > Immersing a 3" long piece of fuel line in fuel for 48 hours caused it to grow to 3 1/8" long. I put a piece of Gates SAE 30R7 in with it, and it grew by exactly the same amount. Fortunately, the ID increased as well, so I am not immediately concerned that it will restrict the fuel flow, but clearly, the fuel is infiltrating the rubber. > > The fuel I'm running right now is 50% 100LL, 50% 91 octane autogas and the appropriate amount of Decalin. There is no measurable ethanol in the mix. > > It's been warm here, so I did a control test to see if temperature would cause expansion and contraction. I put a second 3" sample of each brand in the refrigerator for 48 hours. No change in the length of either one. > > Has anyone experienced this. The last time I used the black rubber automotive line was years ago, so don't know if it did this. I'd certainly be very concerned tho - this doesn't sound like something I'd want to happen in an airplane fuel system...... The main problem with the black rubber line, besides the fact that it can't be inspected, is it's pleated - the pleats can separate under vacuum and the inner wall can collapse with disastrous results. Don't ask my why I know this. The only opaque stuff I'd run would probably be Aeroquip and I'd use that in places where replacing it regularly is very difficult or impossible. I now use Tygothane fuel line which is designed for applications under vacuum like ours generally are. And it doesn't require special fittings like aeroquip does. LS -------- LS Titan II SS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243549#243549 ________________________________ Message 5 _____________________________________ Time: 09:52:46 AM PST US From: "Joe Ronco" Subject: RE: RotaxEngines-List: Fuel Line Growing JIM: Goodyear says for SAE30R9 "WARNING: Do not immerse in gasoline". Both 30R7 and 30R9 have the same outer cover (Black Hypalon-see attached Spec Sheets) so maybe the same warning applies to both? Just a guess. You could also contact Goodyear by phone or e-mail and ask about it. See: http://www.goodyearep.com/contactus.aspx Let us know what they say if you do. Joe R -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Jim Feldmann Sent: Monday, May 11, 2009 9:27 AM Subject: RotaxEngines-List: Fuel Line Growing I just replaced all of the flexible fuel lines (wing tanks to header and firewall forward) with new Goodyear SAE 30R7 rubber fuel line. After a day or two I noticed that the lines seemed to have gotten longer, so I did a test. Immersing a 3" long piece of fuel line in fuel for 48 hours caused it to grow to 3 1/8" long. I put a piece of Gates SAE 30R7 in with it, and it grew by exactly the same amount. Fortunately, the ID increased as well, so I am not immediately concerned that it will restrict the fuel flow, but clearly, the fuel is infiltrating the rubber. The fuel I'm running right now is 50% 100LL, 50% 91 octane autogas and the appropriate amount of Decalin. There is no measurable ethanol in the mix. It's been warm here, so I did a control test to see if temperature would cause expansion and contraction. I put a second 3" sample of each brand in the refrigerator for 48 hours. No change in the length of either one. Has anyone experienced this. -------- Jim Feldmann, 3rd owner 1994 Kitfox IV Speedster / 912 Working on my Sport Pilot Certificate Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243542#243542 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rotaxengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RotaxEngines-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/rotaxengines-list Browse Digests http://www.matronics.com/digest/rotaxengines-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.