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Hi
Charlie:
Thanks for the good
information here. I was struck with a comment you made in an earlier post
that TSIO's shouldn't need the electric fuel pumps except in emergencies.
Both your and Lancair's manual states that it is necessary to turn on the low
boost above 10,000 feet. My engine starts to stumble without the boost at
about 12,000 feet in fact. Were you talking about the high boost?
Or, have I got something of the same problems described here?
After a long, high
altitude, flight, my engine stops running on the runway after pulled to
low idle for landing. (So does the other IVP here on the field)
If I leave the low boost pump on, it not only continues running all right,
but when the mixture is pulled for shut down continues to run as
well. I'm sure this is a vapor lock problem and not part of this
discussion, but the other IVP has tried everything from insulation
to an extra naca duct without success. It seems simple enough to
just use the low boost pump, but this discussion made me wonder if there is a
deeper problem.
Regards,
Bill
Edwards
441JH
-----Original Message-----
From:
Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of Charlie
Kohler
Sent: Tuesday, May 15, 2007 6:17 PM
To:
lml@lancaironline.net
Subject: [LML] Re: Continental Engine fuel
Sys.
Hi Eugene,
I went back and reread your initial post and I feel you were correctly
analyzing the problem.
There is a remote possibility that the vent system is at fault--however it
is hard to believe that both tank vents would be plugged at the same time.
If you remove your fuel cap and put a rubber line into the naca vent and
blow on it--you should feel air coming out the fuel cap. If not-you probably
have a flex line kinked. If you've been flying a while without problems than
it's not likely that the vents are too small.
If all is good here--you have to believe something is wrong with the fuel
system. That consists of three components. Engine-driven fuel pump/fuel
control (throttle valve)/fuel manifold valve.
To have to use the electric fuel pump to keep the engine running below
10,000 feet is indication of a problem and I would not fly the airplane until
I found the problem. You are using your emergency backup system in a normal
operation.
You don't say how many hours or years on the engine. But if these fuel
system components have over five years I would consider them due especially
with the problems you are having.
Charlie K. .
-----
Original Message ---- From: "marv@lancair.net"
<marv@lancair.net> To: lml@lancaironline.net Sent: Tuesday, May
15, 2007 12:06:18 PM Subject: [LML] Re: Continental Engine fuel
Sys.
Posted for "glong2"
<glong2@netzero.net>:
Charlie:
I did the check yesterday.
I drained about 1/5 quarts through the sniffle
valve and did not get a drop
from the manifold valve drain. I was surprised
how fast the high boost pump
put gas in the manifold to the sniffle valve. I
am still looking for a
better explanation than I have!
Have you ever seen a bad manifold valve
diaphragm be intermittent?
This is all good troubleshooting
information, thanks for your input.
Eugene Long
Lancair Super
ES
"""
Actually-- It's a good hangar "floor" preflight check. There
are two
drains-usually on left side by the nose gear door (sniffle valve on
the
right).
One, ( the engine driven fuel pump) may drain oil or fuel--
depending which
seal is leaking. Fuel is especially bad as it is a
precurser to fuel leaking
by the oil seal and filling the
crankcase.
The other drain is the one in the previous post. The fuel
manifold drain.
Another bad (grounding) sign.
A blue stain on the
belly or a spot on the hangar floor is a sign.
By the way-- a black
(oil) spot on ground under sniffle valve on hangar
floor is a indicator
that intake valve guides are worn. If you pull an
intake pipe, you'll find
oil inside. Time to think about a top o'haul.
"""
--
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