Mailing List flyrotary@lancaironline.net Message #17545
From: Paul <sqpilot@bellsouth.net>
Subject: Fuel system changes for SQ2000
Date: Sat, 19 Feb 2005 20:19:27 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Just an update regarding my heat soak/vapor lock fuel issue and fuel system changes. I have successfully duplicated my vapor lock fuel issue several times (on the ground this time). There is little to no doubt that what I experienced was heat related.
      I have firesleeved all fuel lines. I installed a vent line from the top of the sump tank to the top of my left strake fuel tank. (This can easily be removed or replaced with a shraeder valve).
    I have been considering what Tracy, Herb Sanders and a few others have said about the Facet fuel pump possibly being a problem.  I temporarily disconnected the in-line Facet fuel pump and bypassed it with a short length of 3/8" ID clear tubing.  While I had the Facet pump disconnected, I found that I could not blow through it in the direction that is opposite normal fuel flow.  It may be possible, as many have suggested, that any bubbles in the fuel line that would normally be able to work their way uphill and back into the main tanks were prevented from doing so by the one-way Facet fuel pump.  I will run the engine again until it is hot enough to go into it's dying throes of fuel starvation, and observe if there are any bubbles in the newly installed clear fuel line, working their way back towards the tank. Of course if I am lucky and the bubbles work their way to the tank and the engine does not starve for fuel, we may have something here.  I think that the clear tubing may reveal some of it's hidden secrets.  Can't hurt.  I figure the more information I can obtain from my fuel system, the better understanding I will have of it.
    I wish to thank Tracy, Ed, Herb, Al, Jim S, Kelly, Charlie, Perry, Wendell, Mark, Dennis, Bulent, Bill, Tom, Bob, Marvin, Dave, George, Leon, Todd, John, William, (OK I won't go through all the names like an Oscar winner) for all of their input and suggestions. Jim Sower and Herb Sanders even took the time to call me at home.  I am trying a few suggestions one at a time and hopefully I will end up with a vaporlock-free fuel system.
     I have been searching the internet for prefabricated ram air scoops similar to AL's, but so far, most are for car hoods, and too large.  I know I can make one....just getting lazy, and would rather pay for one and be done with it. Thanks again to all who offerd advise and ideas.  I will post results soon.  Take care.  Paul Conner
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