I have an Andair mini gascolator followed by a Y splitting to Andair check
valves
before the pumps in parallel.
I was chatting with Rob Seaton ( of Rotech in canada) at the Rotax display in
Oshkosh.
He recently purchased a 914 powered Europa to use as a test vehicle for
the 912iS. We were talking about fuel system design, how the new 912iS has two
electric pumps like the 914 except higher pressure for the fuel injection.
He said he learned how too small a fuel line and/or tortured routing can cause
"cavitation" at the pumps.
I think that's the same thing, cavitation vs vapor lock? So maybe your fuel
filter(s),
on the suction side of the pump,are causing cavitation in the pump(s).
Maybe due to the size (restriction of flow) of the filter, even if they are
clean.
I do not like the fact that I have a single point of failure in one gascolator.
But if I redesign, I am going to go with less restriction, larger diameter
tubing.
Kevin
On Jul 31, 2012, at 1:57 PM, Frans Veldman <frans@privatepilots.nl> wrote:
>
> On 07/31/2012 07:50 PM, klinefelter.kevin@gmail.com wrote:
>> I have the same system Paul describes. I have not experienced the
>> problem Frans had. But I operate consistently at far higher density
>> altitudes and temps than described.
>
> This is interesting. I think I have the same system as Paul and you
> (With the Andair gascolator) except that I have an additional disposabel
> filter for the secondary fuel pump. We are talking here about the series
> configuration, right?
>
>> Frans, perhaps you are on to something regarding the filters before the
>> pumps causing vaporization of the auto fuel at high density
>> altitude/temp, and perhaps that is the part of the system that is need
>> of redesign.
>
> Well, it could be that the fuel filters are contaminated (although I
> cleaned/replaced them just 40 hours ago) causing enough restriction in
> harsh conditions but not enough to cause a fuel pressure drop at lower
> temps/altitudes. Or I just had a bad batch of fuel.
>
> I will check the system thoroughly and see if I can find any abnormalities.
>
> Frans
>
>
>
>
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