Scott,
You didn’t say what model you are
flying , or the altitude of your airport, but your fuel flow, even when “up”
are still very low for an IO-550. I fly an ES with a IO-550-N, and FF less than
27 gph on takeoff roll is an abort item. Cont says the FF should be between about
28 and 30 gph (about, I don’t have the manual here) at sea level at 2700
RPM.
Another concern I would have is the
routing of the fuel lines from the tanks to the selector, and then electric
fuel pump location. Many of the ES guys went to ½ inch fuel lines, and took
great care to route the lines without sharp corners and without 90 deg elbows
on the way to the selector. We also mounted the electric pump as low as
possible, with some people laying it on the side. On the suction side it easy
to starve the pump, particularly the engine drive one.
Paul Bricker
N63PB
From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf
Of Scott Keighan
Sent: Sunday, July 19, 2009 7:34
PM
To: lml@lancaironline.net
Subject: [LML] Fuel flow issue
Today while flying my first take off was normal. The
second take off my fuel flow
on takeoff went up to 19.0gph then back down to 12.2
after rotation then
slowly went back to normal. Cruised around ok for 15
min then back to the airport
for a couple of circuits. No electric boost pump
except I turned it on for landing.
Next take off the same thing but max Flow on take off
was 18.5gph for half a second then
it went back down to 14.5. Turn on the electric boost and
within 2 seconds its back up to 20.5gph.
Landed and on a back track for another circuit the engine
stalled. Restarted right away with
no issues. Next circuit same issue. Up to
18.0gph then down to 15.0 while rolling down
the runway, hit the boost pump and within 2 seconds all is
well. On downwind switch the
boost pump off and the fuel flow stays in normal
ranges. Take off left or right tank, same issue.
Fuel 25 gal in each tank.
Fuel pressure stays normal the whole time. I
checked for water in the tanks and gascolator.
I checked underneath the cowl for anything out of place.
Engine fuel pump rebuild required?? What do you
think??
Any advise would be appreciated.