---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Thu 12/04/08: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:50 PM - Rough Running 912 (Goodone) 2. 01:40 PM - Re: Rough Running 912 (Roger Lee) ________________________________ Message 1 _____________________________________ Time: 12:50:16 PM PST US Subject: RotaxEngines-List: Rough Running 912 From: "Goodone" I have an 80 HP Rotax 912 UL that I like a lot. Lately I have noticed that there is a slight roughness in the engine if I cruise between about 4200 and 4600 rpm. I have not synchronized the carbs for over 2 years now because the engine seems to run fine at idle speeds less than 1800 rpm and I have been told that any unbalance between the carbs shows up at idle. I dont believe that there is any problem with the plugs. Any suggestions or constructive comments as to what the problem might be or as to how to trouble-shoot would be appreciated. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=217651#217651 ________________________________ Message 2 _____________________________________ Time: 01:40:18 PM PST US Subject: RotaxEngines-List: Re: Rough Running 912 From: "Roger Lee" Hi Goodone, You absolutely do have an unbalanced carbs. That's only because they haven't been balanced in so long. It should be done every 100 hr. or at least at the condition inspection each year if you have low time. Don't let anyone try to convince you otherwise and if someone has been to a Rotax school they absolutely wouldn't make a comment like that. The rough running can absolutely be unbalanced carbs. One side of the engine is trying to run let's say at 4400 rpm and the other at 4500 rpm or worse. Think about what two opposing sides running at different rpm is doing to your engine and gear box over time. One of the most important things to do on your Rotax is to keep the carbs synced. It needs a mechanical and pneumatic sync. It is not hard and should be done asap. Whom ever told you an unbalanced carb sync only shows up at idle doesn't know what they are talking about. No matter what, the carbs will get out of balance over time. They will get out of balance for several reasons. (i.e. cable stretch, worn interior parts, leaks,ect...) How many hours total on these carbs? They may even need a rebuild. It's your hide and pocketbook at stake, so taking 30-60 min. to do a carb sync is cheap insurance. If you need help please don't hesitate to call me. 520-574-1080 -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=217659#217659 ------------------------------------------------------------------------------------- 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.