---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Tue 10/27/15: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:04 AM - Re: Rotax 912S mixture vs mag drop (rampil) ________________________________ Message 1 _____________________________________ Time: 08:04:03 AM PST US Subject: Europa-List: Re: Rotax 912S mixture vs mag drop From: "rampil" Hi Jonathan, The 912 series engines are designed to be fairly tolerant to a wide range of stoichiometric fuel ratios. I surmise this because of the absence of a manual mixture control and the fact that the Bing carbs do close to nothing in terms of altitude adjustment of mixture as I documented here many years ago. Note that the Rotax advertisements no longer claim to be altitude compensating. If anything, in my experience and in chatting with Rotax and Lockwood tech people over the years is that the engine is generally running rich and it gets worse after takeoff. The key purpose of the mag check during run-up is to assess the status of the ignition system to assure that one has two functioning ignitions. The first thing to consider in the differential diagnosis of a large RPM drop on one side of the ignition would ignition problems, e.g., bad or dirty spark plug, bad cable, bad ignition module, etc. Again, my opinion, but I would suggest that fiddling with the carb needles when your base airport is near sea level would be low priority and a low yield procedure. This is not intended as a criticism as you obvious have substantial experience, I just think that many reader here, especially the growing numbers of second or even third generation owners are still just beginning their Rotax education. -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=448309#448309 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-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/europa-list Browse Digests http://www.matronics.com/digest/europa-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.