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----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; <[email protected]> Sent: Sunday, October 23, 2005 5:30 PM Subject: Re: [COUPERS-TECH] Cross-Country Glitches > James: It sounds to me like you need to have a good look at the entire fuel > system. Yes, we did. We also flew the aircraft for several hours before this cross-country without any glitches before the x-country. In other words the header tank was keeping a good head of fuel which was replenished by the wing tanks. Start by checking the two valves, one feeding the fuel pump from the > wing tanks and one feeding the engine from the header tank. Once you have > ascertained that both of the valves are opening completely (I have seen them put > together wrong so they do not fully open (even done it myself)), then check > the lines from the firewall to the pump. (I am assuming you have already > cleaned the pump and replaced the gaskets while properly checking the fuel pump > cover bolt torque). Yes, we did and what it the torque value? I have left the little red pamphlet service manual (from Univair) at Rutherfordton and am in Asheville preparing to drive to Sevierville. The bottom line (from the bottom fitting) goes to the > fitting on the rear of the pump, which is the inlet. The top line comes from the > more forward fitting on the pump (and should have a restriction in it) The flow restrictor is in the line, not in the pump? OK, how would we identify it? It would be something of a diameter pinch in the line? Please describe it. which > is the pump discharge. Yes, we have all that plumbing straight and worked out. We verified it was connected properly by tracing it all out and then running air through the lines. This line comes into the header tank from the rear. Yes. That's hooked up correctly. The aircoupe manual does have a good diagram or drawing showing how to troubleshoot the fuel line connections and assure they are all working properly. > There is another set of lines that come out of the rear of the fuselage > tank, goes into a tee which has two lines that go to either wing tank. > Obviously all of these need to be open and feeding fuel easily. > The lines from the wing tanks come under the floor boards to a tee in > front of the passenger seat then go forward to just ahead of the instrument > panel where the line goes up to the valve on the right side panel. Then from the > valve out to the fuel pump. > I know you have had all of these out of the plane, and have most > certainly checked them carefully, but it may be worth a second check. They have been checked and double-checked. > You should have put new gaskets on the fuel caps when you had the tanks > out to be repaired. We'll do this, have not previously done it and thank you for this advice. Both of the wing tank caps should fit tightly. Well, as a matter of fact they do. They are tight as a tick, so tight they are hard to turn and remove. It sounds > like you may not have enough tension on the springs that hold the cap down on > the one that fuel leaked from, The leak follows the cap with the ram-air hole. If you switch the cap to the other tank, the leak goes with it. The other cap does not leak. The fuel spills during flight from the ram-air hole, NOT from around the lid, or that is the way that it appears to us in the cockpit. however, if there is some problem in the > lines from the fuel pump, i.e. hooked up backwards, especially if you do not have > the restrictor in the fuel pump line, it is possible that you could pump > fuel out of the header and over-fill the wings. > You did not indicate the serial number of the Alon, but if it has fuel > caps that have vent holes in them, I am assuming you have had one or more > service bulletins installed. I received a list of service bulletins from Skyport and find that compliance with the bulletin which requires removing the header tank and cutting a slice out of the top of it and installing new vents is too onerous. We'll do it, of course, if we have no other way out. I believe that the original wing tank caps were the > thermos bottle type and only the header tank was vented. > I apologize for the disjointed discussion of the fuel system. I did not > discuss the overflow vent for the header tank, but it should not be the > problem. > Lynn Nelsen > Here is a list of what I was about to publish in the mail list, particularly in response to a reply of our 'couper friend Ed Burkhart: 1 Gal fuel left in header tank upon landing (owner was sorely affrighted) Plenty fuel in wing tanks Wire gauge in front of windscreen bottomed out and nipple on top disappeared. (trembling and some praying inside aircraft) During flight over mountains, stream of fuel was observed to flow out of ram-air hole in fuel filler cap ON THE WING Not being that familiar with the beast, it was near-death experience (for owner too) After putting down at airport, pump tested by turning prop with starter --- no gasoline flowed A&P/IA trouble-shot the pump from every perspective and declared it defective. (He has worked on Ercoupes before.) He put his mouth over the inlet on the wing tank and blew into the tank to make sure the lines were clear and connected correctly (They were--- In addition to which I tested all of them and the petcocks when I was installing all three tanks. I agree with him and so did a salty A&E also in attendance during the tests Owner said fuel had not ALWAYS streamed from the wing tank lid, which makes me wonder: Do we have a bad flow restrictor, or maybe none at all? I suppose one could fabricate a flow restrictor by drilling a hole of the proper diameter in a tube-shaped billet of aluminum. I work on 172's, Pipers, Taylorcraft, and Cessnas of all types. The shop manuals are just about as thorough as one could ask for, especially Cessna manuals which have great drawings. However, I have yet to see a thorough manual on an Aircoupe and the parts manual is, well, woefully incomplete. ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers-tech/
