Hi Jos
"How do you calculate that?" (failure because of failed Andair 1 way
valve)
I will first mention that my 1988 R100GS BMW motorcycle with type 64 Bing
Carbs has a vacuum controlled valve that turns off fuel to carbs when
there is no vacuum. Let bike sit with MoGas with Stabil (fuel stablizer)
(with carbs run dry) and that valve glues itself closed! Valve is not too
unlike the Andair 1 way valves used by Europa on 914. A very light
pressure to open when working correctly, but 100PSI will not open if glued
shut. Carb cleaner and air can unstick, but almost unbelievable how it can
get so stuck. I have not heard of Andair 1 ways sticking opened or closed,
but my dart throw is sticking closed with MoGas use and sitting plane is
good possible failure.
OK here are some failures Europa 914 series with bypass and 2 filters (or
2 gasculators)**:
**Glue both valves shut, pump #1 on will have a hard time getting through
#2 pump that is off or failed (if both pumps on and they are working will
run OK)
**Glue both valves shut, if #1 pump fails or is off or #1 filter or
gasculator clogged, #2 pump will not provide
**#2 pump fails or is off and #1 valve stuck opened no fuel flow from pump
#1 will be supplied
**#1 pump fails or is off and #2 valve opened no flow from pump #2 will be
supplied
After fooling with system:
http://contrails.free.fr/engine_914_fuel_syst_test_en.php
Good idea to use P1 as primary pump, and good idea to be able to turn off
P1 and run just P2 to test system. If wired so P1 always running you could
not really test #1 valve or #2 filter or Gasculator.
I am using 2 Andair gasculators instead of supplied filters:
http://www.europaowners.org/modules.php?set_albumName=Begin-06-2003&op=modload&name=gallery&file=index&include=view_album.php
See:
Album: 914 modular fuel system. Series with bypass, two Andair 375s.
Another very real failure is having an air leak in Gasculator or Filter!
On my system if I pushed up on one of the beautiful Stainless Steel Andair
bowl drains, just the tiniest bit, either pump #1, or #2 or both #1+#2
would far rather suck air than fuel and foam right away! Thats right, does
not matter Gasculator #1 valve or Gasculator #2 valve, a small leak will
kill fuel flow! Although nice drain, it still relies on an O-Ring to seal.
Worth a very close look before flight no fuel is leaking from those
Gasculator drains, and very careful monitor you have differential pressure
on both pumps, checking 1 pump at a time at high MP.
As one of my tests was to see and touch and feel for my self how the pumps
will perform with a suction head. I noticed that if you create a very
small air leak at either of the Gasculators, it is far more devistating
the greater the suction head. In other words full fuel and nose not too
high will be nowhere near as hard as low fuel level and high nose.
Ron P.
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