---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Tue 08/19/14: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:08 AM - Re: rough running at 3400 RPM and above (kyle Ponsford) 2. 11:44 AM - Re: Re: rough running at 3400 RPM and above (John Hauck) 3. 01:49 PM - Re: Re: rough running at 3400 RPM and above (=?utf-8?Q?J=C3=B3hann_Gestur_J=C3=B3hannsson?=) 4. 04:22 PM - Re: rough running at 3400 RPM and above (kyle Ponsford) ________________________________ Message 1 _____________________________________ Time: 10:08:05 AM PST US Subject: RotaxEngines-List: Re: rough running at 3400 RPM and above From: "kyle Ponsford" Doug, Your descriptions read as if I had written them myself, therefore I was very eager to read to the bottom and see your eventual solution, but I found... NOTHING! Did you ever solve your problem? I have not. My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500 RPM but after that it stumbles/vibrates so badly that it looses power and refuses to push through 4100. but when I pull carb-heat it immediately smooths out and allows me to push it to 4300 RPMs for short periods before falling off dramatically. With the carb-heat "solution" I too came to the early opinion that I was running lean. But I have one significant difference from yours: my plugs are so sooty black they foul about every third flight when I change them. Which leads me to think our identical problems are not plug or fuel related. (I had been running rich plugs to attempt to balance my white #4 cylinder plug due to a factory recognized poor design of the intake header. I have since changed my strategy but that is another issue). I have torn apart my fuel system from one end to the other, cleaned carbs, checked jets, replaced seals and vitnum tipped needles, reset float levels, changed plugs and adjusted plug gaps many times, re-attached the plug wires in their seats and boots, etc. etc. Each time I spend days messing with it until I seem to have solved the problem, go for a few flights before the problem comes back, first small vibrations at the higher end, then more significant vibrations and at progressively lower RPMs until it becomes unflyable again. This has gone on for three years and has greatly mangled my enthusiasm for flying as it keeps me circling my private strip in frustration. Speculations: Recently I had a loose alternator belt on my truck and the engine started to loose power and run very poorly but it continued to run at low RPMs. I tightened the belt and solved my problem. It got me to thinking that I may be having a similar problem with my magnetos. This is so recent a thought that I have not yet began to explore how to check my mags when the engine won't run in the region that needs testing. Then I found your thread here. PLEASE tell me you finally figured out the actual solution but failed to post it here! I am very, very interested. - Kyle Read this topic online here: http://forums.matronics.com/viewtopic.php?p=428766#428766 ________________________________ Message 2 _____________________________________ Time: 11:44:21 AM PST US From: "John Hauck" Subject: RE: RotaxEngines-List: Re: rough running at 3400 RPM and above My first flight to Alaska in 1994, my 912 had a similar problem. Eventually raised the fuel needles one notch and corrected the problem. Seems the old 80 horse is really sensitive to lean conditions at midrange. The way I eventually discovered the fix was pulling the enricher full on during flight at about 4,200 rpm. The engine gained 200 rpm. john h mkIII Titus, Alabama -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of kyle Ponsford Sent: Tuesday, August 19, 2014 12:07 PM Subject: RotaxEngines-List: Re: rough running at 3400 RPM and above --> Doug, Your descriptions read as if I had written them myself, therefore I was very eager to read to the bottom and see your eventual solution, but I found... NOTHING! Did you ever solve your problem? I have not. My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500 RPM but after that it stumbles/vibrates so badly that it looses power and refuses to push through 4100. but when I pull carb-heat it immediately smooths out and allows me to push it to 4300 RPMs for short periods before falling off dramatically. With the carb-heat "solution" I too came to the early opinion that I was running lean. But I have one significant difference from yours: my plugs are so sooty black they foul about every third flight when I change them. Which leads me to think our identical problems are not plug or fuel related. (I had been running rich plugs to attempt to balance my white #4 cylinder plug due to a factory recognized poor design of the intake header. I have since changed my strategy but that is another issue). I have torn apart my fuel system from one end to the other, cleaned carbs, checked jets, replaced seals and vitnum tipped needles, reset float levels, changed plugs and adjusted plug gaps many times, re-attached the plug wires in their seats and boots, etc. etc. Each time I spend days messing with it until I seem to have solved the problem, go for a few flights before the problem comes back, first small vibrations at the higher end, then more significant vibrations and at progressively lower RPMs until it becomes unflyable again. This has gone on for three years and has greatly mangled my enthusiasm for flying as it keeps me circling my private strip in frustration. Speculations: Recently I had a loose alternator belt on my truck and the engine started to loose power and run very poorly but it continued to run at low RPMs. I tightened the belt and solved my problem. It got me to thinking that I may be having a similar problem with my magnetos. This is so recent a thought that I have not yet began to explore how to check my mags when the engine won't run in the region that needs testing. Then I found your thread here. PLEASE tell me you finally figured out the actual solution but failed to post it here! I am very, very interested. - Kyle Read this topic online here: http://forums.matronics.com/viewtopic.php?p=428766#428766 ________________________________ Message 3 _____________________________________ Time: 01:49:17 PM PST US Subject: Re: RotaxEngines-List: Re: rough running at 3400 RPM and above From: =?utf-8?Q?J=C3=B3hann_Gestur_J=C3=B3hannsson?= Hello Kyle. My friend had the exact same problem you have. He had been messing with his Rotax 912 ul engine since he bought it. Same as your experiance, seemed to have solved it but the rough running always came back. Finally he found the problem. The Stator was the original part and had been a recallmon that part, but it had not been replaced at the correct time. So my advice is to replace the stator. You can find the recall information from the Rotax on the stator. Hope this helps, Johann G. Sent from my iPad > On Aug 19, 2014, at 5:06 PM, "kyle Ponsford" wrote: > > > Doug, > Your descriptions read as if I had written them myself, therefore I was very eager to read to the bottom and see your eventual solution, but I found... NOTHING! > Did you ever solve your problem? I have not. > > My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500 RPM but after that it stumbles/vibrates so badly that it looses power and refuses to push through 4100. but when I pull carb-heat it immediately smooths out and allows me to push it to 4300 RPMs for short periods before falling off dramatically. With the carb-heat "solution" I too came to the early opinion that I was running lean. > But I have one significant difference from yours: my plugs are so sooty black they foul about every third flight when I change them. Which leads me to think our identical problems are not plug or fuel related. > (I had been running rich plugs to attempt to balance my white #4 cylinder plug due to a factory recognized poor design of the intake header. I have since changed my strategy but that is another issue). > > I have torn apart my fuel system from one end to the other, cleaned carbs, checked jets, replaced seals and vitnum tipped needles, reset float levels, changed plugs and adjusted plug gaps many times, re-attached the plug wires in their seats and boots, etc. etc. > Each time I spend days messing with it until I seem to have solved the problem, go for a few flights before the problem comes back, first small vibrations at the higher end, then more significant vibrations and at progressively lower RPMs until it becomes unflyable again. This has gone on for three years and has greatly mangled my enthusiasm for flying as it keeps me circling my private strip in frustration. > > Speculations: > Recently I had a loose alternator belt on my truck and the engine started to loose power and run very poorly but it continued to run at low RPMs. > I tightened the belt and solved my problem. > It got me to thinking that I may be having a similar problem with my magnetos. This is so recent a thought that I have not yet began to explore how to check my mags when the engine won't run in the region that needs testing. > Then I found your thread here. > PLEASE tell me you finally figured out the actual solution but failed to post it here! I am very, very interested. > > - Kyle > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=428766#428766 > > > > > > > > > > ________________________________ Message 4 _____________________________________ Time: 04:22:50 PM PST US Subject: RotaxEngines-List: Re: rough running at 3400 RPM and above From: "kyle Ponsford" Johann G., I am grateful for your information/suggestion and will tackle that idea immediately! Thanks, - Kyle Read this topic online here: http://forums.matronics.com/viewtopic.php?p=428799#428799 ------------------------------------------------------------------------------------- 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.