---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Thu 06/28/07: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:55 AM - Re: egt temp (Thom Riddle) ________________________________ Message 1 _____________________________________ Time: 03:55:22 AM PST US From: Thom Riddle Subject: Re: RotaxEngines-List: egt temp Noel, When you used the term "backfire" I mistakingly thought you were referring to the explosion in the exhaust system phenomenon, which is what many (maybe most) people erroneously call "backfiring" when in truth that is an "afterfire". Afterfiring being generally caused by unburned fuel (from overly rich condition) in the exhaust system hitting a hot spot and exploding. With your further explanation I now know you were speaking of firing back through the intake system, which indeed can be caused by lean condition among others. Thanks for the clarification. You are also correct when you state that when the fuel level in the float bowl is low that would cause a lean condition, whether it is caused by the fuel supply being exhausted or the float level is set too low. I'm well acquainted with the rich of peak and lean of peak situations and in general, especially with engines that are not fuel injected or in which instrumentation does not include EGT for every cylinder, your recommendation to run a bit rich of peak EGT is a good one. However, in a system with manual mixture control, as long as I'm running at normal cruise power or less, I generally lean very slowly until the slightest roughness begins to be noticed and then enrichen mixture until smooth again. As long as the fuel is of the proper octane and everything else is normal in the engine, this will yield best fuel economy without risking the engine in any way. Unfortunately, we don't have a manual mixture control on our 912UL. Thom in Buffalo ------------------------------------------------------------------------------------- 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.