---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Tue 12/13/11: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:24 AM - Re: Carb synch issues (Roger Lee) 2. 05:30 AM - Re: Carb synch issues (David Weaver) ________________________________ Message 1 _____________________________________ Time: 05:24:03 AM PST US Subject: RotaxEngines-List: Re: Carb synch issues From: "Roger Lee" You should have no problems syncing at 3500 and then at idle. Some of you use a very thick throttle cable (i'e. vernier type) and or have to tight a bend in the cables. Many times it isn't the carb that won't sync, but the throttle cable that causes you grief. This will usually let you set the high sync, but will make the idle sync tougher to zero. The issue is that each time you pull the throttle cable back and forth it never exactly goes back to the same idle point on each carb which makes you think they aren't synced. I just did an RV12 and that's what's wrong with that throttle cable system. The cables are thick and there are bends which makes the cable bind just enough to drive you crazy on a sync at idle. You may need to physically push the throttle arms back into an idle position by hand to get them all the way down instead of allowing the throttle in the cockpit do it. If you have thin enough cables and no tight bends and the cables move freely then syncing the idle shouldn't be an issue. Start with the mechanical sync to get you close. Some carbs are a little more finicky too. Instead of moving one side idle stop screw you may need to screw one out a little and one in a little. You may not be able to just move one screw. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Repair Center - Heavy Maint. Rated Home 520-574-1080 TRY HOME FIRST Cell 520-349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=360822#360822 ________________________________ Message 2 _____________________________________ Time: 05:30:39 AM PST US From: David Weaver Subject: Re: RotaxEngines-List: Carb synch issues The carb sync procedure from Rotax does not address those installations, li ke yours and mine, where it is not possible to achieve even throttle cable pull throughout the full range of travel.- Tether your airplane (I use he avy rope attached to lower landing gear legs with wheel chalks) and sync yo ur carbs in upper RPM range only.- Forget the low RPM range since the goa l is to achieve smooth engine operation in RPM range where-the engine-i s under load.- I frankly do not care what my Carb Tune tool is indicating at engine idle (which is smooth with little prop loading).- I go for clo se to 5,000 RPM to do my carb balancing and like very much the results I ge t both at cruise in flight and at engine idle.- If it were up to me, I wo uld change the published carb tune procedure as I have a header tank in my XP and can not route the unequal length throttle cables to achieve even car b throttle arm pull through out the-range of travel. Dave Weaver N912GR --- On Mon, 12/12/11, egp8111 wrote: From: egp8111 Subject: RotaxEngines-List: Carb synch issues I can't get the carbs on my 912ul to synch at both idle and about 4000rpm. - If I adjust it for one setting it runs rough at the other.- I'm using the dual throttle cable from ACS .- Any suggestions ? thanks, EG Read this topic online here: http://forums.matronics.com/viewtopic.php?p=360765#360765 le, List Admin. le, List Admin. ------------------------------------------------------------------------------------- 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.