What
fuel pressure range should I be seeing for a Lycoming IO-360 in a Lancair 360
(N360DE)?
The
fuel pressure is indicating between 16 and 18 without the boost pump on.
When I go to altitudes above 6,000 feet, the fuel pressure drops a pound
or two so I turn on the boost pump. With the boost pump on fuel pressure
in indicated between 18 and 20 PSI.
What is
interesting is that the VM 1000 (where Fuel Pressure is indicated) has a red
arc section, a yellow arc section, and a green arc section. At the fuel
pressures I am seeing; 16 PSI is in the top end of the yellow arc, so 17 to 20
PSI appears in the lower range of the green arc – giving us the feeling that
we are on the ragged edge of not having proper fuel pressure for normal
operation.
The
VM-1000 can be calibrated so that the proper fuel pressure indicates more
properly in the green arc – if this is proper.
Information
that may be important to know:
IO-360
Model = Started life as
O-360-C2A and converted to an IO-360 – S/N
L-21393-36A
Fuel
pressure is taken after the mechanical
pump, 1 foot before the fuel servo on a tee
fitting.
Fuel
system/model/etc. = Bendix, model RSA
5AD1, parts list 2524213-10 less issues -11, S/N
9354/10
Have
any components (fuel pump, servo, flow-divider, nozzles, etc.)
been modified? = Fuel servo mod: there was a mod made to the
servo fuel injector to reverse the actuation of the butterfly valve and the
fuel-metering valve. When the throttle arm was rotated full forward;
this was the idle position of the butterfly valve and the fuel-metering valve.
We had this reversed so that full forward position resulted in full
throttle.
No other
mods.
What type
mechanical (engine-driven) fuel pump (diaphragm or
rotary)? =
Diaphragm
Thanks in
advance.
Randy
Hartman