---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 12/17/07: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:39 AM - Re: 912ULS: Carburettor and Airbox venting lines (Martin Pohl) 2. 10:00 AM - Re: 912ULS: Carburettor and Airbox venting lines (N601RT) 3. 05:07 PM - Re: 912ULS: Carburettor and Airbox venting lines (Roger Lee) 4. 06:09 PM - Re: Re: 912ULS: Carburettor and Airbox venting lines () ________________________________ Message 1 _____________________________________ Time: 09:39:21 AM PST US Subject: RotaxEngines-List: Re: 912ULS: Carburettor and Airbox venting lines From: "Martin Pohl" Roger, that sounds fair! I will do it the same way. Thx and cheers Martin -------- Martin Pohl Zodiac XL QBK 8645 Jona, Switzerland www.pohltec.ch/ZodiacXL Read this topic online here: http://forums.matronics.com/viewtopic.php?p=152702#152702 ________________________________ Message 2 _____________________________________ Time: 10:00:53 AM PST US Subject: RotaxEngines-List: Re: 912ULS: Carburettor and Airbox venting lines From: "N601RT" Martin and Roger, (This is my first posting to this list. I've been lurking for a while.) Be very careful of routing the carb vent lines. I personally saw a CH701 have significantly reduced power from routing the carb vent lines to the bottom of the cowl. Everything was fine during ground testing, but the plane would barely climb. Changing the vent line back to the original length solved his problem. There have been reports of others having problems with other installations where the vent line was improperly extended. (Remember this is a vent line as you have properly discussed; It IS NOT a fuel overflow line.) I took the Rotax Maintenance course at California Power Systems that Eric Tucker taught in early 2005. Eric stressed the importance of making sure the pressure at the vent line is the same as the pressure around the carb. He specifically said DO NOT extend the vent line to the bottom of the cowl as this has the chance of reducing the pressure the vent line senses and can prevent the carb slide from opening fully. I've routed standard length vent line into a much larger tube which goes to the bottom of my cowl. There is about 3/4inch of the smaller line in the larger line. This allows any fuel that might come out of the vent line to flow into the larger line AND it allows the vent line to have the same pressure at the carb. Regards, Roy N601RT: 2002 CH601HDS, nose gear, Rotax 912ULS, Arplast PV-50, All electric, IFR, equipped, 895hrs Read this topic online here: http://forums.matronics.com/viewtopic.php?p=152707#152707 ________________________________ Message 3 _____________________________________ Time: 05:07:48 PM PST US Subject: RotaxEngines-List: Re: 912ULS: Carburettor and Airbox venting lines From: "Roger Lee" I agree that the vent lines are not supposed to be in the slip stream, but just down by the bottom of the cowling, but still inside should be fine. -------- Roger Lee Tucson, Az. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=152789#152789 ________________________________ Message 4 _____________________________________ Time: 06:09:04 PM PST US Subject: Re: RotaxEngines-List: Re: 912ULS: Carburettor and Airbox venting lines From: Just a note on 912/S: Increase float bowl pressure over ambient pressure = richer mixture Decrease float bowl pressure below ambient pressure = leaner mixture As a matter of fact these guys sell a kit that allows you to decrease float bowl pressure (lean mixture) by pulling a vacuum through a needle valve (or automatic) via manifold cross over tube: http://www.greenskyadventures.com/bing/HACmanorder.htm Choose an area in cowl that is ambient pressure on ground and especially in flight. One good location is just downstream of air filter, or go measure chosen location on ground and in flight (climb, dive, go fast and slow, flaps and clean). Ron Parigoris BTW 914 is a different beast, you need to vent float bowl to air-box pressure (to accommodate turbo charging). As a matter of fact, for 115% 914 power operations the TCU rich-ens the mixture a little by plumbing float bowl pressure via a solenoid from air-box pressure to above air-box pressure (scoop in air-box airstream that increases pressure). None the less theory of increasing float bowl pressure above some value to richen, and decreasing float bowl pressure below some value to lean is the same as 912/S. MAKE SURE FLOAT BOWL PLUMBING IS FREE OF RESTRICTIONS OR LEAKS ON ALL 9XXs. ------------------------------------------------------------------------------------- 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.