Today's Message Index:
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1. 01:08 AM - The report (so far) on the "Case of the missing fuel" (MPPalmer@aol.com)
2. 03:48 AM - Re: The report (so far) on the "Case of the missing fuel" (Robert Feldtman)
3. 06:44 AM - Re: The report (so far) on the "Case of the missing fuel" (Doug Dodson)
4. 07:25 AM - Re: The report (so far) on the "Case of the missing fuel" (Craymondw@aol.com)
Message 1
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| Subject: | The report (so far) on the "Case of the missing fuel" |
Just got back from the hanger. (It's past midnight. Too hot to work in the
hangar during the day in Phoenix.) Here's what I've done so far.
I ran the electric fuel pump off the header tank for about 15 minutes. I
rotated the prop thru (backward) slowly, two rotations, listening for any change
in pump frequency. I figured, by rotating the prop, I would be moving the
diaphragm on the fuel pump through its various positions on the cam. If I found
a
place where the diaphragm was leaking, I would hear it. Also, I would be able
to see the fuel level change on the header tank. (We have a sight gage.) So
far, nothing. No leak at the fuel pump overflow. No fuel smell in the oil. No
change in header fuel level.
I'll plan to do the test again tomorrow, maybe more exhaustively by clocking
the prop at 8 points twice, and letting it sit there for a minute or two.
I disconnected the vents at the center section of the fuse. So far, no
obstructions. But, to be totally thorough, I'm gonna have to pull the wing tips
and
disconnect the center section runners and blow them down from there. (That
should be a lot of fun.)
We have a carburetor. I'm hard pressed to imagine we could be blowing a few
gallons out of it, but I suppose if the needle valve sticks in flight, it could
happen. You would think I would notice the mixture going super rich in flight
and/or massive staining on the cowl (plus fumes in the cockpit) if the float
stuck, but I'll pull the cowl and look around. It was recently overhauled and
shouldn't be sticking, but ...
I can't believe that 100LL has changed, but since I'm running out of ideas,
has anyone heard if 100LL is evaporating more than it used to?
Has anyone ever had a Flowscan transducer miss pulses? Ours is located
downstream of the electric fuel pump, so it should be getting semi-filtered fuel.
But it's 13 years old, with almost 3000 hours on it. Maybe the ball has worn out
and fuel slips by uncounted?
We had a 5 angle valve job done on the cylinders a year ago... I suppose we
could simply be burning more gas with an errant transducer not reporting it.
But then we should have noticed the discrepancy in fuel used starting last year
and it doesn't seem this has been a problem until the past few months.
I haven't yet broached the idea of fuel leaking in the wing.... can you lose
a few gallons that way without smelling it in the fuselage?
Mike Palmer <><<BR><BR><BR>**************<BR>Gas prices getting you down? Search
AOL Autos
for fuel-efficient used cars.<BR>
(http://autos.aol.com/used?ncid=aolaut00050000000007)
Message 2
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| Subject: | Re: The report (so far) on the "Case of the missing fuel" |
leaking in the wing you will smell it. my right fuel tank vent tubing came
off (broke) at the coupling and fuel was sloshing out the vent when taxiing
and the tank was topped off full. the smell was very evident. fixed easily
by identifying the problem (thanks to this list and suggestion to look) -
bobf
glastar
On 7/8/08, MPPalmer@aol.com <MPPalmer@aol.com> wrote:
>
> Just got back from the hanger. (It's past midnight. Too hot to work in the
> hangar during the day in Phoenix.) Here's what I've done so far.
>
> I ran the electric fuel pump off the header tank for about 15 minutes. I
> rotated the prop thru (backward) slowly, two rotations, listening for any
> change in pump frequency. I figured, by rotating the prop, I would be moving
> the diaphragm on the fuel pump through its various positions on the cam. If
> I found a place where the diaphragm was leaking, I would hear it. Also, I
> would be able to see the fuel level change on the header tank. (We have a
> sight gage.) So far, nothing. No leak at the fuel pump overflow. No fuel
> smell in the oil. No change in header fuel level.
>
> I'll plan to do the test again tomorrow, maybe more exhaustively by
> clocking the prop at 8 points twice, and letting it sit there for a minute
> or two.
>
> I disconnected the vents at the center section of the fuse. So far, no
> obstructions. But, to be totally thorough, I'm gonna have to pull the wing
> tips and disconnect the center section runners and blow them down from
> there. (That should be a lot of fun.)
>
> We have a carburetor. I'm hard pressed to imagine we could be blowing a few
> gallons out of it, but I suppose if the needle valve sticks in flight, it
> could happen. You would think I would notice the mixture going super rich in
> flight and/or massive staining on the cowl (plus fumes in the cockpit) if
> the float stuck, but I'll pull the cowl and look around. It was recently
> overhauled and shouldn't be sticking, but ...
>
> I can't believe that 100LL has changed, but since I'm running out of ideas,
> has anyone heard if 100LL is evaporating more than it used to?
>
> Has anyone ever had a Flowscan transducer miss pulses? Ours is located
> downstream of the electric fuel pump, so it should be getting semi-filtered
> fuel. But it's 13 years old, with almost 3000 hours on it. Maybe the ball
> has worn out and fuel slips by uncounted?
>
> We had a 5 angle valve job done on the cylinders a year ago... I suppose we
> could simply be burning more gas with an errant transducer not reporting it.
> But then we should have noticed the discrepancy in fuel used starting last
> year and it doesn't seem this has been a problem until the past few months.
>
> I haven't yet broached the idea of fuel leaking in the wing.... can you
> lose a few gallons that way without smelling it in the fuselage?
>
> Mike Palmer <><
>
>
> **************
> Gas prices getting you down? Search AOL Autos for fuel-efficient used cars.
> (http://autos.aol.com/used?ncid=aolaut00050000000007)
>
> *
>
> *
>
>
Message 3
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| Subject: | The report (so far) on the "Case of the missing fuel" |
Mike,
You only mention in this last message that the fuel computer was in
error. Have you confirmed the fuel loss with direct measurements of the
fuel quantity?
You can accurately measure your fuel burn rate by filling one tank,
climbing up to a cruise altitude on another tank, switching to the full
tank and fly with a properly leaned mixture at a fixed power setting for
an hour. Land on the other tank then re-fill. You can do the same
thing but don't use one tank or the other to see if fuel is leaving one
tank or the other in flight.
- Doug
-----Original Message-----
From: owner-glasair-list-server@matronics.com
[mailto:owner-glasair-list-server@matronics.com] On Behalf Of
MPPalmer@aol.com
Sent: Tuesday, July 08, 2008 1:05 AM
Subject: Glasair-List: The report (so far) on the "Case of the missing
fuel"
Just got back from the hanger. (It's past midnight. Too hot to work in
the hangar during the day in Phoenix.) Here's what I've done so far.
I ran the electric fuel pump off the header tank for about 15 minutes. I
rotated the prop thru (backward) slowly, two rotations, listening for
any change in pump frequency. I figured, by rotating the prop, I would
be moving the diaphragm on the fuel pump through its various positions
on the cam. If I found a place where the diaphragm was leaking, I would
hear it. Also, I would be able to see the fuel level change on the
header tank. (We have a sight gage.) So far, nothing. No leak at the
fuel pump overflow. No fuel smell in the oil. No change in header fuel
level.
I'll plan to do the test again tomorrow, maybe more exhaustively by
clocking the prop at 8 points twice, and letting it sit there for a
minute or two.
I disconnected the vents at the center section of the fuse. So far, no
obstructions. But, to be totally thorough, I'm gonna have to pull the
wing tips and disconnect the center section runners and blow them down
from there. (That should be a lot of fun.)
We have a carburetor. I'm hard pressed to imagine we could be blowing a
few gallons out of it, but I suppose if the needle valve sticks in
flight, it could happen. You would think I would notice the mixture
going super rich in flight and/or massive staining on the cowl (plus
fumes in the cockpit) if the float stuck, but I'll pull the cowl and
look around. It was recently overhauled and shouldn't be sticking, but
...
I can't believe that 100LL has changed, but since I'm running out of
ideas, has anyone heard if 100LL is evaporating more than it used to?
Has anyone ever had a Flowscan transducer miss pulses? Ours is located
downstream of the electric fuel pump, so it should be getting
semi-filtered fuel. But it's 13 years old, with almost 3000 hours on it.
Maybe the ball has worn out and fuel slips by uncounted?
We had a 5 angle valve job done on the cylinders a year ago... I suppose
we could simply be burning more gas with an errant transducer not
reporting it. But then we should have noticed the discrepancy in fuel
used starting last year and it doesn't seem this has been a problem
until the past few months.
I haven't yet broached the idea of fuel leaking in the wing.... can you
lose a few gallons that way without smelling it in the fuselage?
Mike Palmer <><
**************
Gas prices getting you down? Search AOL Autos for fuel-efficient used
cars.
(http://autos.aol.com/used?ncid=aolaut00050000000007)
Message 4
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| Subject: | Re: The report (so far) on the "Case of the missing fuel" |
A Glasair 2 owner in Fort Walton Beach Fla. developed a leak in his spar. He
found it by noticing blue dye around a tie down hole. He didn't smell fumes
because the fuel never got past the wing rib. I would try a fuel tank
pressure test to see if it holds pressure.
Also, I once had a float needle not seal.
**************Gas prices getting you down? Search AOL Autos for
fuel-efficient used cars. (http://autos.aol.com/used?ncid=aolaut00050000000007)
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