---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 01/30/12: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:14 AM - Re: 912 80 hp back-fire on shutdown (ejessee) 2. 06:40 AM - Re: Re: 912 80 hp back-fire on shutdown (David Weaver) 3. 06:58 AM - Re: Re: 912 80 hp back-fire on shutdown (Dashwoodlock) 4. 07:57 AM - Re: Re: 912 80 hp back-fire on shutdown (Richard Girard) 5. 07:58 AM - Re: Re: 912 80 hp back-fire on shutdown (Richard Girard) 6. 08:22 AM - Re: 912 80 hp back-fire on shutdown (Jason Omelchuck) 7. 09:57 AM - Re: 912 80 hp back-fire on shutdown (ejessee) 8. 06:57 PM - Re: 912 80 hp back-fire on shutdown (dashwood) ________________________________ Message 1 _____________________________________ Time: 06:14:23 AM PST US Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: "ejessee" Dave, Thank you for the information. This "crab Idle jet"... is that in the carburetor? -------- Ernest Jessee N4931M Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365207#365207 ________________________________ Message 2 _____________________________________ Time: 06:40:39 AM PST US From: David Weaver Subject: Re: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown No....that discomfort which some may suffer when flying was not what I was referring to.- The typo was not intended to cast me as a comedian.- I w ill strive toward better editing in the future. Dave Weaver --- On Mon, 1/30/12, ejessee wrote: From: ejessee Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown Dave, Thank you for the information.- This "crab Idle jet"... is that in the ca rburetor? -------- Ernest Jessee N4931M Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365207#365207 le, List Admin. ________________________________ Message 3 _____________________________________ Time: 06:58:17 AM PST US From: Dashwoodlock Subject: Re: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown if you have to ask this question. you have to get an engine mechanic to do the work... --- On Mon, 1/30/12, ejessee wrote: From: ejessee Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown Received: Monday, January 30, 2012, 9:11 AM Dave, Thank you for the information.- This "crab Idle jet"... is that in the ca rburetor? -------- Ernest Jessee N4931M Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365207#365207 le, List Admin. ________________________________ Message 4 _____________________________________ Time: 07:57:07 AM PST US Subject: Re: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: Richard Girard Sounds like something from "Spongebob Squarepants" doesn't it? Clearly, too much time watching videos with my five year old grandson. Rick On Mon, Jan 30, 2012 at 8:11 AM, ejessee wrote: > > Dave, > Thank you for the information. This "crab Idle jet"... is that in the > carburetor? > > -------- > Ernest Jessee > N4931M > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=365207#365207 > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 5 _____________________________________ Time: 07:58:03 AM PST US Subject: Re: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: Richard Girard Dave, Hope you didn't mind the ribbing. It was pretty good comic relief and a smile or laugh is invaluable these days. Rick On Mon, Jan 30, 2012 at 8:38 AM, David Weaver wrote: > No....that discomfort which some may suffer when flying was not what I was > referring to. The typo was not intended to cast me as a comedian. I will > strive toward better editing in the future. > Dave Weaver > > --- On *Mon, 1/30/12, ejessee * wrote: > > > From: ejessee > Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown > To: rotaxengines-list@matronics.com > Date: Monday, January 30, 2012, 8:11 AM > > > > > Dave, > Thank you for the information. This "crab Idle jet"... is that in the > carburetor? > > -------- > Ernest Jessee > N4931M > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=365207#365207 > > > onics.com/Navigator?RotaxEngines-List" target=_blank>http://www.matronics; > -Maww.matronics.com/contribution" ====== > > > * > > * > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 6 _____________________________________ Time: 08:22:54 AM PST US Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: "Jason Omelchuck" Technically a back fire is through the carbs and an after fire comes out of the exhaust. It might be possible that the heat wrapping on the exhaust allows the exhaust pipes to get hot enough to ignite a fuel air mixture. When you turn the engine off, it pumps some un-burned mixture through the engine where it is ignited in the exhaust. my $.02 worth Jason ejessee wrote: > Hello all, > I did a search in the forum with "backfire", "back-fire", and "back fire" with no results, So here goes.... > > I have an 80 hp 912 UL on a Zenith 701. When I return to my hangar after flight, unless I do a 2 -3 minute stabilization run at 2100 RPM, my 912 backfires like a shotgun when I turn it off. I have newly rebuilt carbs, perfectly balanced carbs, plugs at .024. The engine runs perfect, uses no oil. My exhaust stacks are heat-wrapped. As severely as it backfires, I am afraid I am going to damage my exhaust system. > > Anyone else ever experience this? Anybody know what is causing it. Is something wrong or is this just the nature of the engine. > > AS always, thanks for your help. This forum is a fantastic resource. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365224#365224 ________________________________ Message 7 _____________________________________ Time: 09:57:51 AM PST US Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: "ejessee" Thanks. I have suspected the heat wrap as perhaps adding to the problem. As for the implication that I should get a mechanic... Hey.. I just missed the joke. I conduct my plane maintenance with humility and try to get someone to check my work, but I am very capable. I have rebuilt my airframe, and have worked on virtually every sub-system on my engine. The A&P who helps me with conditionals says my plane is one of the best maintained he has every worked on. I am not intimately familiar with the name of jets in the carbs. Sorry for taking a bit of offense. I just hate condescension. -------- Ernest Jessee N4931M Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365232#365232 ________________________________ Message 8 _____________________________________ Time: 06:57:57 PM PST US Subject: RotaxEngines-List: Re: 912 80 hp back-fire on shutdown From: "dashwood" sorry if i sounded condescending. my humblest apologies. i was on a tight schedule at work and didn't have time to elaborate. I agree the problem is likely in the carb jetting /blockage. at the idle setting. it sounds like the idle rpm is correct. is there any exhaust leaks hidden by the wraps.. i was always told that backfiring had to have oxygen induced to ignite the unburnt gasses. backfiring opens the hole to cause more backfiring to cause bigger hole .. and around we go. the unburnt fuel has to be coming from somewhere though.??one bad carb and one good one would be hard to notice. maybe a little more vibration. but a partial flooding of one side would only show on the plugs at that point of shutdown... remember that you will find a variety of blackness inherent in rotax engines b/c of the poor intake manifolds dispersement. Pleas keep us informed on what you find... -------- Ross Aalexander: CH701 driver 912ul 589tt It only takes two things to fly, airspeed and money Read this topic online here: http://forums.matronics.com/viewtopic.php?p=365270#365270 ------------------------------------------------------------------------------------- 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.