---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Sun 07/21/13: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:03 PM - Re: RotaxEngines-List Digest: 8 Msgs - 07/10/13 (Ralph K. Hallett III) 2. 04:56 PM - Fuel distribution banjo fittings (Richard Girard) 3. 07:51 PM - Starting carburetors (Richard Girard) 4. 08:00 PM - Re: Re: RotaxEngines-List Digest: 8 Msgs - 07/10/13 (Richard Girard) ________________________________ Message 1 _____________________________________ Time: 01:03:27 PM PST US From: "Ralph K. Hallett III" Subject: RotaxEngines-List: Re: RotaxEngines-List Digest: 8 Msgs - 07/10/13 A quick question for you all. I have a 912S in a Rans S7. Out of the blue the oil pressure gauge is rapidly swinging from high to low followed by a pause at the correct oil pressure. Then more of the same. This only happens after flying for 20 min or so in 70F weather. I figured it must be the sender unit which is attached to the block near the oil pump. I got the same readings on the next flight. Reducing the engine to idle causes the gauge to settle down. However, here's where it gets interesting, I noticed that all the gauges, tach, oil temp, oil pressure and voltage are stable at the beginning of the flight but when the oil pressure starts to swing wildly the other gauges too have started to vibrate, not to the extent of the oil pressure. I'm starting to become suspicious that the voltage regulator is getting ready to crap out. Thoughts? Ralph Reno, NV ________________________________ Message 2 _____________________________________ Time: 04:56:47 PM PST US Subject: RotaxEngines-List: Fuel distribution banjo fittings From: Richard Girard Okay, the airplane I am working on was built without a fuel return line. I am trying to figure out the correct banjo fittings for getting fuel from the pump, a line to each carburetor, and a return line. The IPS is clear as mud. I want to use a 851327 clamp block with a 840518 allen screw and a 641733 slotted head screw and a 230150 gasket ring Can I use two double hose nipples # 956602, one for the line from the fuel pump and the return line with a 963820 pilot jet in it, and one for going to each carb? Do I need two banjo bolts or one? (p/n please) What is in the 941785 banjo bolt assy? All of the above minus the clamp block and its hardware? Much thanks to anyone who can lead me through this morass. Rick Girard It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 3 _____________________________________ Time: 07:51:25 PM PST US Subject: RotaxEngines-List: Starting carburetors From: Richard Girard The airplane has ~500 hours on it and the 912 ULS. Except for one logbook entry for carburetor cleaning it appears that this was the first carb rebuild. The needle valves in both carbs failed and both would overflow within three to four blade cold cranking. The starting carburetors, which had worked flawlessly seemed to have failed, the engine was hard starting. I rebuilt one carb at a time to always have a complete carb for reference and to avoid mixing parts. I started with the right carb (overflow tube pointed outboard. When I pulled the starting carb housing I found the inboard end of the shaft was stamped "L". Staining on the disk seemed to indicate that the slot was properly positioned so that when it was rotated the slot was moved over the port connected to the float bowl. The rebuild was a complete overhaul, all gaskets, o rings, diaphragms and floats were replaced, as was the needle and needle jet. I located the dot on the outboard end of the starting carb shaft so that it pointed toward the cable and lightly tightened the four screws of the housing. Disassembly of the left carb (overflow tube pointing inboard) revealed that the starting carburetor shaft was stamped on the inboard end "R". Again, staining on the disk showed that the slot uncovered the port from the float bowl when it was rotated. At this point I was beginning to doubt my sanity. I considered that German for Right starts with and "L". It doesn't. I thought perhaps Rotax directed right and left as seen with from the prop end of the engine. From what I could find in the Installation Manual, right and left are relative to the pilot looking forward with the engine mounted in a tractor installation. Since the history of the engine seemed to show that the starting carbs were working until recently, but had stopped working (I should add that there was no sign that the starting carbs had been opened before I did) I decided to put the disk assembly with the shaft stamped "R" in the right carb and put the "L" disk in the left carb. Because the airplane's owner wants to overhaul the fuel system to include a fuel return line to control fuel pressure, we did not attempt to start the engine when I re-installed the carbs today. The possibilities seem to be; A. Both starting carbs were miss assembled with a right shaft mated to a left disk and vice versa. B. I have misinterpreted the Installation manual and right and left orientation are relative to the prop end of the engine. C. These carbs were originally installed in the Twilight Zone. Comments? Advise? Rick Girard -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 4 _____________________________________ Time: 08:00:56 PM PST US Subject: Re: RotaxEngines-List: Re: RotaxEngines-List Digest: 8 Msgs - 07/10/13 From: Richard Girard Check engine to airframe grounds and instrument grounds first. Rick Girard do not archive On Sun, Jul 21, 2013 at 3:02 PM, Ralph K. Hallett III wrote: > n100rh@sbcglobal.net> > > A quick question for you all. I have a 912S in a Rans S7. Out of the blue > the oil pressure gauge is rapidly swinging from high to low followed by a > pause at the correct oil pressure. Then more of the same. This only happens > after flying for 20 min or so in 70F weather. I figured it must be the > sender unit which is attached to the block near the oil pump. I got the > same readings on the next flight. Reducing the engine to idle causes the > gauge to settle down. > However, here's where it gets interesting, I noticed that all the gauges, > tach, oil temp, oil pressure and voltage are stable at the beginning of the > flight but when the oil pressure starts to swing wildly the other gauges > too have started to vibrate, not to the extent of the oil pressure. > I'm starting to become suspicious that the voltage regulator is getting > ready to crap out. Thoughts? > > Ralph > Reno, NV > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ------------------------------------------------------------------------------------- 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.