---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Wed 05/31/06: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:18 AM - Re: oil level (Airgriff2@aol.com) 2. 04:30 AM - Re : Re: oil level (Gilles.Thesee@ac-grenoble.fr) 3. 06:13 AM - Re: 912 idle speed adjustment (=?ISO-8859-1?Q?J=F3hann_Gestur?=) 4. 06:44 AM - Re: 912 idle speed adjustment (Thom Riddle) 5. 10:31 AM - 2 Msgs - 05/30/06 (Erol Onderoglu) 6. 01:45 PM - Re: Re: 912 idle speed adjustment (Peter Rees) 7. 03:14 PM - Re: 912 idle speed adjustment (Thom Riddle) 8. 03:52 PM - Re: Re: 912 idle speed adjustment (Duncan McFadyean) ________________________________ Message 1 _____________________________________ Time: 04:18:22 AM PST US From: Airgriff2@aol.com Subject: Re: RotaxEngines-List: oil level Thanks Tom. Is it 3 liters or 3 qts ? We didn't do the crankcase plug. Thanks for the heads up. A friend stopped last night and answered my question (I believe) about the oil coming out of the tank when I rotated the prop after hearing it gurgle. He said the oil system works by pumping oil from the engine to the tank and back through the engine. When I heard the Gurgle and rotated more, an additional amount of air was sent to the tank as it would normally pressurize the tank and send oil back to the engine. With the cap off the pressure sent the oil out of the top. Think of it as if the engine was running, circulating the oil between the tank and engine and what would happen if you took off the cap at that point. I guess the procedure is to stop when you 1st hear the air enter the tank. Fly Safe Bob Griffin Albany NY ________________________________ Message 2 _____________________________________ Time: 04:30:14 AM PST US From: Gilles.Thesee@ac-grenoble.fr Subject: Re : Re: RotaxEngines-List: oil level Bob and all, Is it 3 liters or 3 qts ? The oil capacity is depending not only on the engine, but also on your specific installation, oil lines, radiator and all. See the Operator's manual which came withe the engine. We didn't do the crankcase > plug. According to Rotax SBs, you should not open the crankcase plug during ordinary oil changes You may want to refer to the Operator and Maintenance manuals for further information. If you don't have them, thy can be downloaded from the Rotax website. Regards, Gilles Thesee http://contrails.free.fr ________________________________ Message 3 _____________________________________ Time: 06:13:54 AM PST US From: =?ISO-8859-1?Q?J=F3hann_Gestur?= Subject: Re: RotaxEngines-List: 912 idle speed adjustment --> RotaxEngines-List message posted by: =?ISO-8859-1?Q?J=F3hann_Gestur?= Hello Thom. I have the same engine and just did the balance adjustments on the carbs, but the gage showed me that the timing was off. Not sure how to adjust that on this engine? But the idle speed can not be adjusted below 1800, because the engine will not run at lower speed. My adjustments were done on a hot engine, i.e. normal oil temp. The gage I used were the same as sold by Lockwood and CPS. I would appreciate any ideas on how to adjust the engine so that it may run at lower idle speeds such as 1400 rpm. Thanks, Johann G. Thom Riddle wrote: > --> RotaxEngines-List message posted by: Thom Riddle > > > During our annual inspection we balanced the carbs on the 912UL and > adjusted the idle speed to 1400 rpm after the oil temperature was up > to 120F. With the carbs. balanced the idle is much smoother than > before. However, after flying the airplane for about an hour with the > oil temps up into the normal operations range around 215F, when > closing the throttle the idle speed went down to well under 1400 rpm. > > My question: Must the engine be up to normal operating oil temp > (190-230F) when adjusting the idle speed? > > Thom in Buffalo > > ________________________________ Message 4 _____________________________________ Time: 06:44:11 AM PST US Subject: RotaxEngines-List: Re: 912 idle speed adjustment From: "Thom Riddle" --> RotaxEngines-List message posted by: "Thom Riddle" Johann, Before our annual inspection our engine was idling (a bit roughly due to vaccumm inbalance) at 1400 rpm with no problem, other than roughness. My old Titan Tornado, sold recently, had the same engine and it idled smoothly at 1400 rpm. It was that way when I got it and I never touched the carbs. During the inspection we put the dual vaccumm gauges on the engine and noticed that the vaccumm readings were different by about 2 inches so we balanced them quickly but the idle was not smooth until we repinstalled the balance tube. We then adjusted both idle speed screws the same amount to get it down to 1400 rpm. All this was done after warming up the engine on the ground to 120F oil temp. After flying the airplane the next day, when fully warmed up, the idle speed was well below 1400 rpm. Our next step, this afternoon will be to increase the idle speed to perhaps 1600 rpm at 120F and see how it does after flying it to normal temps. Final adjustment will be made right after the flight while it is near normal operating temperature. It is my understanding that the Rotax 912 series engines have no way for the owner/operator to adjust the timing. It is fixed at the factory and not adjustable. Your inability to get the engine to idle smoothly at 1400 rpm is due to carb vaccumm inbalance. Use the gauges according to the Rotax manual to do this. Do NOT expect it to idle smoothly while doing this because it probably won't without the balance tube connected to both carbs. If you make sure the two vaccumm gauges read the same, when you put the balance tube back on it should idle smoothly at some rpm, then adjust each idle speed screw the exact same amount to maintian the balance and change the idle speed. The purpose of using the vaccumm gauges is to make sure that both carbs are opening the same amount at idle. My original question was merely about what temperature the engine should be running at to adjust the idle speed. Apparently, to do it right, it must be up to normal op. temps., not just 120F. Thom in Buffalo FAA Powerplant Mechanic - but relatively new to Rotax w/ multiple carbs. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=37640#37640 ________________________________ Message 5 _____________________________________ Time: 10:31:54 AM PST US From: "Erol Onderoglu" Subject: RotaxEngines-List: 2 Msgs - 05/30/06 --- MIME Errors - No Plain-Text Section Found --- A message with no text/plain MIME section was received. The entire body of the message was removed. Please resend the email using Plain Text formatting. HOTMAIL is notorious for only including an HTML section in their client's default configuration. If you're using HOTMAIL, please see your email application's settings and switch to a default mail option that uses "Plain Text". --- MIME Errors No Plain-Text Section Found --- ________________________________ Message 6 _____________________________________ Time: 01:45:43 PM PST US From: "Peter Rees" Subject: Re: RotaxEngines-List: Re: 912 idle speed adjustment --> RotaxEngines-List message posted by: "Peter Rees" Can I please ask - where did the figure of 1400 RPM come from?? I was under the impression that the minimum recommended idle speed was 1700. The Rotax service manual specifically states that idle speeds that are too low will result in gearbox wear / damage. Are we setting ours too high or are you too low? Peter ----- Original Message ----- From: "Thom Riddle" Sent: Wednesday, May 31, 2006 2:43 PM Subject: RotaxEngines-List: Re: 912 idle speed adjustment > --> RotaxEngines-List message posted by: "Thom Riddle" > > > Johann, > > Before our annual inspection our engine was idling (a bit roughly due to > vaccumm inbalance) at 1400 rpm with no problem, other than roughness. My > old Titan Tornado, sold recently, had the same engine and it idled > smoothly at 1400 rpm. It was that way when I got it and I never touched > the carbs. > > During the inspection we put the dual vaccumm gauges on the engine and > noticed that the vaccumm readings were different by about 2 inches so we > balanced them quickly but the idle was not smooth until we repinstalled > the balance tube. We then adjusted both idle speed screws the same amount > to get it down to 1400 rpm. All this was done after warming up the engine > on the ground to 120F oil temp. > > After flying the airplane the next day, when fully warmed up, the idle > speed was well below 1400 rpm. Our next step, this afternoon will be to > increase the idle speed to perhaps 1600 rpm at 120F and see how it does > after flying it to normal temps. Final adjustment will be made right after > the flight while it is near normal operating temperature. > > It is my understanding that the Rotax 912 series engines have no way for > the owner/operator to adjust the timing. It is fixed at the factory and > not adjustable. > > Your inability to get the engine to idle smoothly at 1400 rpm is due to > carb vaccumm inbalance. Use the gauges according to the Rotax manual to > do this. Do NOT expect it to idle smoothly while doing this because it > probably won't without the balance tube connected to both carbs. If you > make sure the two vaccumm gauges read the same, when you put the balance > tube back on it should idle smoothly at some rpm, then adjust each idle > speed screw the exact same amount to maintian the balance and change the > idle speed. The purpose of using the vaccumm gauges is to make sure that > both carbs are opening the same amount at idle. > > My original question was merely about what temperature the engine should > be running at to adjust the idle speed. Apparently, to do it right, it > must be up to normal op. temps., not just 120F. > > Thom in Buffalo > FAA Powerplant Mechanic - but relatively new to Rotax w/ multiple carbs. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=37640#37640 > > > ________________________________ Message 7 _____________________________________ Time: 03:14:56 PM PST US Subject: RotaxEngines-List: Re: 912 idle speed adjustment From: "Thom Riddle" --> RotaxEngines-List message posted by: "Thom Riddle" Peter, It is in the Rotax 912 series Operators Manual in Section 10.1.1) Operating Speeds and Limits (912 UL/A/F). -------- Thom in Buffalo Read this topic online here: http://forums.matronics.com/viewtopic.php?p=37740#37740 ________________________________ Message 8 _____________________________________ Time: 03:52:49 PM PST US From: "Duncan McFadyean" Subject: Re: RotaxEngines-List: Re: 912 idle speed adjustment --> RotaxEngines-List message posted by: "Duncan McFadyean" On some aircraft (eg Europa) a fast idle speed will result in too much residual thrust and difficulty in landing within a reasonably short distance. A low idle speed helps in this temporary situation, although the engine does not then have to be left at a low idle speed once the landing is complete. Duncan Mcf. ----- Original Message ----- From: "Peter Rees" Sent: Wednesday, May 31, 2006 9:42 PM Subject: Re: RotaxEngines-List: Re: 912 idle speed adjustment > --> RotaxEngines-List message posted by: "Peter Rees" > > > Can I please ask - where did the figure of 1400 RPM come from?? I was > under the impression that the minimum recommended idle speed was 1700. The > Rotax service manual specifically states that idle speeds that are too low > will result in gearbox wear / damage. Are we setting ours too high or are > you too low? > > Peter > > > ----- Original Message ----- > From: "Thom Riddle" > To: > Sent: Wednesday, May 31, 2006 2:43 PM > Subject: RotaxEngines-List: Re: 912 idle speed adjustment > > >> --> RotaxEngines-List message posted by: "Thom Riddle" >> >> >> Johann, >> >> Before our annual inspection our engine was idling (a bit roughly due to >> vaccumm inbalance) at 1400 rpm with no problem, other than roughness. My >> old Titan Tornado, sold recently, had the same engine and it idled >> smoothly at 1400 rpm. It was that way when I got it and I never touched >> the carbs. >> >> During the inspection we put the dual vaccumm gauges on the engine and >> noticed that the vaccumm readings were different by about 2 inches so we >> balanced them quickly but the idle was not smooth until we repinstalled >> the balance tube. We then adjusted both idle speed screws the same amount >> to get it down to 1400 rpm. All this was done after warming up the engine >> on the ground to 120F oil temp. >> >> After flying the airplane the next day, when fully warmed up, the idle >> speed was well below 1400 rpm. Our next step, this afternoon will be to >> increase the idle speed to perhaps 1600 rpm at 120F and see how it does >> after flying it to normal temps. Final adjustment will be made right >> after the flight while it is near normal operating temperature. >> >> It is my understanding that the Rotax 912 series engines have no way for >> the owner/operator to adjust the timing. It is fixed at the factory and >> not adjustable. >> >> Your inability to get the engine to idle smoothly at 1400 rpm is due to >> carb vaccumm inbalance. Use the gauges according to the Rotax manual to >> do this. Do NOT expect it to idle smoothly while doing this because it >> probably won't without the balance tube connected to both carbs. If you >> make sure the two vaccumm gauges read the same, when you put the balance >> tube back on it should idle smoothly at some rpm, then adjust each idle >> speed screw the exact same amount to maintian the balance and change the >> idle speed. The purpose of using the vaccumm gauges is to make sure that >> both carbs are opening the same amount at idle. >> >> My original question was merely about what temperature the engine should >> be running at to adjust the idle speed. Apparently, to do it right, it >> must be up to normal op. temps., not just 120F. >> >> Thom in Buffalo >> FAA Powerplant Mechanic - but relatively new to Rotax w/ multiple carbs. >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=37640#37640 >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> > > > http://www.matronics.com/Navigator?RotaxEngines-List > http://wiki.matronics.com > > >