Newshound Posted April 30, 2012 Author Report Share Posted April 30, 2012 HelloIf Anyone could assist me I would Really appreciate it !!When I do a mag test @ 3800 RPM their is no noticeable drop between the two on power up I get good RPM when reaching 1000 foot after take off i level off and come off the power to 4800 for the cruise or 5000 RPM the engine runs very rough not smooth @ all when i increase the RPM to 5250 5300 it then sounds better i first though i might be experiencing Carb icing but after 1 hour of flying it still stayed the same on the descent i brought it back to 3000 RPM sounded very smooth i landed checked that the choke on boath sides were up against the stops and they were i had just had the carbs balance about four flights ago because i notice it did the same at 4600 and at 5000 it was smooth now this problem is getting progresively worse so I have opted to stop flying untill it has been sorted out I also tried in flight to activate the fuel pump but to help any advice would be greatley appreciated Please.Kind RegardsCharlieMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 30, 2012 Author Report Share Posted April 30, 2012 My 912 ULS has this crack on the upper side of the crankcase, in the middle between the cylinder pairs.Does anyone know what's behind this crack, inside of the engine?Or - is there any drawing available to find out what is inside - any bearings, or just air?More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 30, 2012 Author Report Share Posted April 30, 2012 My 912 ULS has this crack on the upper side of the crankcase, in the middle between the cylinder pairs.Does anyone know what's behind this crack, inside of the engine?Or - is there any drawing available to find out what is inside - any bearings, or just air?More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 30, 2012 Author Report Share Posted April 30, 2012 In the old days before cars had fuel injection I (and many reputable mechanics) considered part of a routine tune up to idle the engine and spray a few puffs of carb cleander right down into the carb. I could always actually see this process cleaning brown deposits out of the throat.Short of taking of carbs and doing the complete clean and rebuild,anyone here ever do that on their 912 or 914?(I did talk to one 912 owner sho does this, but figured I'd check here too.)Anyone think of any harm in doing so (as long as you don't foolishly put your body in the way of the spinning prop)?Or better yet do the spray and clean with the engine warm but totally off?(seems saner to me -- but would have to do one carb at a time, restart, let engine clear out the cleaner from carb one, turn off and do the other.That is, because based on my old experience with 4 cycle auto engines, the engine may not be too happy about starting with the peculiar mixture of fuel, air, and carb cleaner in BOTH carbs.)If viable, this seems like a easy way to do a bit of carb cleaning between major carb rebuilds.AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 30, 2012 Author Report Share Posted April 30, 2012 In the old days before cars had fuel injection I (and many reputable mechanics) considered part of a routine tune up to idle the engine and spray a few puffs of carb cleander right down into the carb. I could always actually see this process cleaning brown deposits out of the throat.Short of taking of carbs and doing the complete clean and rebuild,anyone here ever do that on their 912 or 914?(I did talk to one 912 owner sho does this, but figured I'd check here too.)Anyone think of any harm in doing so (as long as you don't foolishly put your body in the way of the spinning prop)?Or better yet do the spray and clean with the engine warm but totally off?(seems saner to me -- but would have to do one carb at a time, restart, let engine clear out the cleaner from carb one, turn off and do the other.That is, because based on my old experience with 4 cycle auto engines, the engine may not be too happy about starting with the peculiar mixture of fuel, air, and carb cleaner in BOTH carbs.)If viable, this seems like a easy way to do a bit of carb cleaning between major carb rebuilds.AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 1, 2012 Author Report Share Posted May 1, 2012 Anyone know what the ideal and acceptable range and variation (difference between cyclinders) of compression readings (hot and/or cold engine) are for a standard automotive type compression test on Rotax 912UL?(Preferably in PSI)And at what indicators/reading of pressure does one have either indicators of signficant wear or problems?I waded through a lot of Rotax documentation and couldn't seem to find that info for the standard (non-leakdown) compression tests. There was lots of info on using and interpreting the leakdown test.Couldn't find much on the standard test, other than it is an alternate method.I realize the leakdown compression test is preferable but not an option right now.AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 1, 2012 Author Report Share Posted May 1, 2012 Anyone know what the ideal and acceptable range and variation (difference between cyclinders) of compression readings (hot and/or cold engine) are for a standard automotive type compression test on Rotax 912UL?(Preferably in PSI)And at what indicators/reading of pressure does one have either indicators of signficant wear or problems?I waded through a lot of Rotax documentation and couldn't seem to find that info for the standard (non-leakdown) compression tests. There was lots of info on using and interpreting the leakdown test.Couldn't find much on the standard test, other than it is an alternate method.I realize the leakdown compression test is preferable but not an option right now.AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 1, 2012 Author Report Share Posted May 1, 2012 Hello,I have a Rotax 912 80 hp that has flown about 80 hrs. I have changed at 50 hrs oil+filter and filled the oil up to about the max level.Checking oil level today after its famous burping the oil level is just above min level.Is this normal?JanMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 1, 2012 Author Report Share Posted May 1, 2012 Hello,I have a Rotax 912 80 hp that has flown about 80 hrs. I have changed at 50 hrs oil+filter and filled the oil up to about the max level.Checking oil level today after its famous burping the oil level is just above min level.Is this normal?JanMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 2, 2012 Author Report Share Posted May 2, 2012 I'm thinking of installing a fuel flow monitor for our 912ULS. It's fed from L+R tanks and has a backup electric pump. I think I will need two sensors (one for fuel in and one for fuel return) and a unit which calculates the difference and maybe displays the pressure as well. The prices of sensors seem ridiculous for what they are.Anybody out there with experience of these. I'm contemplating picking something up at OshkoshMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 2, 2012 Author Report Share Posted May 2, 2012 I'm thinking of installing a fuel flow monitor for our 912ULS. It's fed from L+R tanks and has a backup electric pump. I think I will need two sensors (one for fuel in and one for fuel return) and a unit which calculates the difference and maybe displays the pressure as well. The prices of sensors seem ridiculous for what they are.Anybody out there with experience of these. I'm contemplating picking something up at OshkoshMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 2, 2012 Author Report Share Posted May 2, 2012 I am in the Phoenix area and have a 914 that has a problem with the turbo not working. I need a competent technician that is experienced with the neuances of the engine and can resolve my problem that several good technicians have not been able to fix. My plane is currently at Chandler Az after a cross country trip from Florida.Anyone who would recommend a technician, please let me know. My next step if I can't get this problem solved is to get it to Rotax Support in British Columbia.ThanksMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 2, 2012 Author Report Share Posted May 2, 2012 I am in the Phoenix area and have a 914 that has a problem with the turbo not working. I need a competent technician that is experienced with the neuances of the engine and can resolve my problem that several good technicians have not been able to fix. My plane is currently at Chandler Az after a cross country trip from Florida.Anyone who would recommend a technician, please let me know. My next step if I can't get this problem solved is to get it to Rotax Support in British Columbia.ThanksMore... Quote Link to comment Share on other sites More sharing options...
Michael Haisten Posted May 2, 2012 Report Share Posted May 2, 2012 Bernard,If you would like to come Auburn California, I have experience with the 914 and the turbo control unit.Michael HaistenAuburn Airplane Works Quote Link to comment Share on other sites More sharing options...
Michael Haisten Posted May 2, 2012 Report Share Posted May 2, 2012 Bernard,If you would like to come Auburn California, I have experience with the 914 and the turbo control unit.Michael HaistenAuburn Airplane Works Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 3, 2012 Author Report Share Posted May 3, 2012 Anyone of a 914 Tech in the Western US?More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 3, 2012 Author Report Share Posted May 3, 2012 Anyone of a 914 Tech in the Western US?More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 5, 2012 Author Report Share Posted May 5, 2012 Greetings all,Here's my dilemma. I am an LSRM-A working on an SLSA. I've got a somewhat older (~2007 vintage) Rotax 912ULS with a VDO-style oil pressure sensor and a TL Elektronik engine monitor. The pressure sensor is mounted directly to the oil pump housing.This engine is showing fluctuating oil pressure. The pressure will fluctuate in and out of the acceptable range, as in 45, 52, 53, 102, 44, 23, 97... numbers in PSI.There are several places I can think of to find the problem.I've watched the video on this site on the subject, and it describes removing both the electric sensor and the pressure relief valve. The video leaves out what I consider to be VITAL information: Should you purge the oil system after either one of these services?My money is on the sensor. I've replaced one of these sensors before (and performed the purge procedure just in case), but the only sensor available now is the Honeywell variable current styel sensor. That P.O.S. TL engine monitor has a password that nobody knows, so I can't get into it to change the settings. According to SI-912-020, the resistive-type VDO sensor "...is not suitable anymore." In context, this is a very vague statement. Does this mean that VDO sensors are no longer authorized for use on 912's, or that VDO sensors aren't compatible with the wiring for Honeywell-equipped engines? Can I legally replace this VDO sensor if I manage to find an identical unit, or must I install a Honeywell sensor? If I have to use a Honeywell sensor, it means a new engine monitor.I doubt the issue is caused by engine vibration, but it's a plausible reason for the early failure. I'll have to talk with the airframe manufacturer about moving the sensor to the firewall. I have a temporary mechanical gauge, so I can do that check if need be.So, to recap: Should I purge the oil system after removing the sensor, relief valve, or both? And can I install a new VDO sensor if I find one?Thanks in advance,AdamLSRM-A CFI-SPMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 5, 2012 Author Report Share Posted May 5, 2012 Greetings all,Here's my dilemma. I am an LSRM-A working on an SLSA. I've got a somewhat older (~2007 vintage) Rotax 912ULS with a VDO-style oil pressure sensor and a TL Elektronik engine monitor. The pressure sensor is mounted directly to the oil pump housing.This engine is showing fluctuating oil pressure. The pressure will fluctuate in and out of the acceptable range, as in 45, 52, 53, 102, 44, 23, 97... numbers in PSI.There are several places I can think of to find the problem.I've watched the video on this site on the subject, and it describes removing both the electric sensor and the pressure relief valve. The video leaves out what I consider to be VITAL information: Should you purge the oil system after either one of these services?My money is on the sensor. I've replaced one of these sensors before (and performed the purge procedure just in case), but the only sensor available now is the Honeywell variable current styel sensor. That P.O.S. TL engine monitor has a password that nobody knows, so I can't get into it to change the settings. According to SI-912-020, the resistive-type VDO sensor "...is not suitable anymore." In context, this is a very vague statement. Does this mean that VDO sensors are no longer authorized for use on 912's, or that VDO sensors aren't compatible with the wiring for Honeywell-equipped engines? Can I legally replace this VDO sensor if I manage to find an identical unit, or must I install a Honeywell sensor? If I have to use a Honeywell sensor, it means a new engine monitor.I doubt the issue is caused by engine vibration, but it's a plausible reason for the early failure. I'll have to talk with the airframe manufacturer about moving the sensor to the firewall. I have a temporary mechanical gauge, so I can do that check if need be.So, to recap: Should I purge the oil system after removing the sensor, relief valve, or both? And can I install a new VDO sensor if I find one?Thanks in advance,AdamLSRM-A CFI-SPMore... Quote Link to comment Share on other sites More sharing options...
Guest chasers03 Posted May 6, 2012 Report Share Posted May 6, 2012 I have the same engine in my 2005 Lambada and my PSI would fluctuate but not as bad as yours. I replaced the relief valve completely with the new style and the fluctuation / often 2 bar readings went away and now I read higher usually 3 bars on my TL. I did not purge the system as not that much oil leaked out. I think I also burped the engine before replacement. I recommend you first do as I did before changing the sensor. Steve Chase 864 903 5493 in SC. Quote Link to comment Share on other sites More sharing options...
Guest chasers03 Posted May 6, 2012 Report Share Posted May 6, 2012 I have the same engine in my 2005 Lambada and my PSI would fluctuate but not as bad as yours. I replaced the relief valve completely with the new style and the fluctuation / often 2 bar readings went away and now I read higher usually 3 bars on my TL. I did not purge the system as not that much oil leaked out. I think I also burped the engine before replacement. I recommend you first do as I did before changing the sensor. Steve Chase 864 903 5493 in SC. Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 7, 2012 Author Report Share Posted May 7, 2012 I finally got around to installing my fuel pressure gauge on my KitFox Vixen 912UL. The gauge is a Holley electric round gauge c/w sender unit mounted just downstream from the original mechanical fuel pump (mid 90`s engine)In flight the gauge reads a steady 5 psi at all times. Yesterday I shut off the fuel while taxiing in and ran the engine until the pressure bled off to less that 1 psi. I then restarted and instantly got 5 psi again. I then let the plane sit for 15 minutes or so and the pressure remained at 5 psi. After 30 or more minutes the pressure gradually increases to around 10 psi.I believe what is happening is that the fuel is expanding from heat dissipating from the engine. The fuel cannot escape through the carb float valve or back through the pump so it just pressures up. Over the years occasionally I have hot start problems about 30 or so minutes after shut down and I always suspected "vapour lock". I now believe it is over-pressured hot fuel blasting into the carbs and FLOODING!!.I now understand why Rotax is recommending a return fuel line back to the gascolator or tank.Roger, could you advise what size of restrictor orifice I should have in my return line that I will be installing this week. What about an adjustable valve set to maintain the 5 psi at cruise RPM?ThanksDonMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 7, 2012 Author Report Share Posted May 7, 2012 I have a question about initial engine runs of a new 912ULS. Most engine builders of Lycoming or TCM engines prefer you not ground run the engine more than is absolutely essential to adjust it for takeoff. The danger is glazing the cylinder bores. I can find no reference to this in any of the Rotax guidance. My DAR wants me to taxi test for around 2 hours which is really insane I think. Any idea if prolonged taxi prior to first flight will possibly damage the 912 engine.Thanks,BradMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 7, 2012 Author Report Share Posted May 7, 2012 I finally got around to installing my fuel pressure gauge on my KitFox Vixen 912UL. The gauge is a Holley electric round gauge c/w sender unit mounted just downstream from the original mechanical fuel pump (mid 90`s engine)In flight the gauge reads a steady 5 psi at all times. Yesterday I shut off the fuel while taxiing in and ran the engine until the pressure bled off to less that 1 psi. I then restarted and instantly got 5 psi again. I then let the plane sit for 15 minutes or so and the pressure remained at 5 psi. After 30 or more minutes the pressure gradually increases to around 10 psi.I believe what is happening is that the fuel is expanding from heat dissipating from the engine. The fuel cannot escape through the carb float valve or back through the pump so it just pressures up. Over the years occasionally I have hot start problems about 30 or so minutes after shut down and I always suspected "vapour lock". I now believe it is over-pressured hot fuel blasting into the carbs and FLOODING!!.I now understand why Rotax is recommending a return fuel line back to the gascolator or tank.Roger, could you advise what size of restrictor orifice I should have in my return line that I will be installing this week. What about an adjustable valve set to maintain the 5 psi at cruise RPM?ThanksDonMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted May 7, 2012 Author Report Share Posted May 7, 2012 I have a question about initial engine runs of a new 912ULS. Most engine builders of Lycoming or TCM engines prefer you not ground run the engine more than is absolutely essential to adjust it for takeoff. The danger is glazing the cylinder bores. I can find no reference to this in any of the Rotax guidance. My DAR wants me to taxi test for around 2 hours which is really insane I think. Any idea if prolonged taxi prior to first flight will possibly damage the 912 engine.Thanks,BradMore... Quote Link to comment Share on other sites More sharing options...
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