---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 08/10/09: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:52 AM - Re: loss of compression (Catz631@aol.com) 2. 05:04 AM - Re: Re: loss of compression (Catz631@aol.com) 3. 05:49 AM - Re: Re: loss of compression (Dave Austin) 4. 10:43 AM - Re: loss of compression (rparigor@suffolk.lib.ny.us) ________________________________ Message 1 _____________________________________ Time: 04:52:49 AM PST US From: Catz631@aol.com Subject: Re: RotaxEngines-List: loss of compression Roger, If I pull back on my throttle all the way on the ground it will go back to about 1400 rpm. This equates to a minimum of aprox 1800 in the air due to the airflow. I have it set this way so that I can slow down and land the airplane. Previously I had it set higher and it was difficult to get the aircraft slow enough and out of ground effect. I don't allow the engine to idle at 1400. 1800 is my minimum. I use a Vernier throttle to control it The only time I was using 1400 was at engine shutdown at the end of a flight (and that was on the recommendation of one of the 4 Rotax distributors in the country) I am aware of the damage that can occur to the gearbox with continued low rpm settings. I saw the results on some gearbox parts at my Rotax class (many years ago). The 1400 shutdown is for a very short time in an effort to stop the" kick back". (but I will use the higher rpm method and higher octane fuel) My carbs are in sync. I did that about 8 hrs ago BUT I did not check the float heights. I will give that a shot! Thanks again for your tips! Dick Maddux Rotax 912 UL Milton,Fl ________________________________ Message 2 _____________________________________ Time: 05:04:42 AM PST US From: Catz631@aol.com Subject: Re: RotaxEngines-List: Re: loss of compression Dave, If your oil tank is high (which mine is) then the oil will tend to siphon into the crankcase when you shutdown the engine. They mentioned that in my Lockwood Rotax class which I attended years ago.( and in Kitfox bulletins) The location is the only place to mount the oil tank on the early Kitfoxes so I have to live with it.(changed on the newer airplanes) The lines are full of oil so the hot oil just starts a small reverse flow. It takes awhile for a lot of oil to drain into the crankcase but that is the reason you turn the prop thru before you fly the aircraft. You are moving this oil out of the crankcase back into the oil tank.( also to check the actual oil level) Dick Maddux Rotax 912 UL Milton,Fl ________________________________ Message 3 _____________________________________ Time: 05:49:29 AM PST US From: "Dave Austin" Subject: Re: RotaxEngines-List: Re: loss of compression Hi Dick, My oil tank is just above the dry sump. Maybe that's why I don't get the syphoning. Maybe a check valve is the answer to your situation. How many turns of the prop does it take to get the oil back into the tank? Dave Austin 601HDS - 912 ________________________________ Message 4 _____________________________________ Time: 10:43:16 AM PST US Subject: Re: RotaxEngines-List: loss of compression From: rparigor@suffolk.lib.ny.us Hi Dick Not flying my 914 yet but a few ideas on shut down kickback. *I have heard that when you get ignition modules hot, the first thing that happens is that when you ground them, they may not shut down, or partially shut down. Just for hahas before a very hot shut down at 1400 RPM give a mag check and see if you get any coughing on one or both mags. *On a hot engine there could be glowing carbon that could give a firing when you don't want one. I had a 1972 yamaha RT-2 360 thatI removed spark plug on a hot engine and proceeded to take a compression test, got a firing and trashed my gauge! You could try pulling choke for 15 seconds before and during shut down?? *Did you adjust low speed mixture? You may want to adjust them on a very hot engine on a very hot day, or do as manual says find highest RPM and instead of richening (I think it is 1/2 turn, please check manual) go a slight bit richer. Ron Parigoris ------------------------------------------------------------------------------------- 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.