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At 10:17 PM 12/13/2005, [EMAIL PROTECTED] wrote:
1. On days when the temperature rises moderately and the plane is
sitting in the hangar, fuel will leak out of the header tank cap
vent and on to the cowl. This happens most often during the summer,
but has also occurred during the fall on days with temperatures in
the 50s - 60s. I thought that the fuel should flow back into the
wing tanks via the overflow lines.
There are a number of possible fuel system configurations, and
ultimately the answer depends on which one you have, however, here
are some generalities.
First, there may be an overflow line inside the tank that vents
excess fuel out the bottom of the cowl. If plugged, it could cause
what you're seeing. Second, if the vent lines for the wing tanks are
below the level of the fuel in the tanks and the wing tank caps are
not vented, fuel cannot flow back to the wings. Unvented wing tanks
should be coupled with the over flow mentioned above.
2. When it is flying, the header tank fuel indicator will rise to
full shortly after I level off. Last week during a 30-minute
flight, fuel appeared in the glass tube that covers the header tank
indicator. About 1/2" at most. It was gone by the time I landed.
Is the sight tube sealed at the top? if so, it should not be
possible for fuel to migrate into the tube.
Tonight I flew the plane for about 15 minutes. After I landed, a
shot of fuel came out of the header tank vent and covered the wind
screen for a few seconds.
Sounds like the header tank may be over filling. Is the restriction
present in the outlet fitting of the fuel pump? Also, IIRC, the
recommended fill procedure leaves an inch of airspace in each wing tank.
After I shut it down I opened both wing caps. I heard pressure
leaving each of them. The left wing tank was full, but the right was
down noticeably.
How much?
John Cooper
Skyport Services
PO Box 249
4996 Delaware Tnpk
Rensselaerville, NY 12147
518 797-3064
Fax 518 797-3865
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