Hi! Hans.
Early Rotax/912 Europa aircraft instructions were to fit a restrictor in the
return line. This was a simple plug with a fine bore hole in it, they even
provided the plug.
I don't know the origin of your aircraft or fuel system but I do know that
this restrictor is not required in the 914 system.
Check out your installation as to if it has the restrictor in it? They were
simply held in place by a jubilee clip clamping it in place. I have heard of
such restrictors just buggering off down the line after the clips have
relaxed.
Check that out too.
Regards
Bob Harrison. G-PTAG
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Hans J.
Danielsen
Sent: 17 October 2010 11:18
Subject: Re: Europa-List: Too high fuel pressure
Thank you Jan for your good advice! I'll lokk into the problem on Monday.
Ragards
Hans
----- Original Message -----
From: "Jan de Jong" <jan_de_jong@casema.nl>
Sent: Sunday, October 17, 2010 2:39 AM
Subject: Re: Europa-List: Too high fuel pressure
>
> From your description I would still suspect the return line. Is there a
> 1-way valve in there?
> A way to test it would be to connect the forward line (from the pumps)
> directly to the return line using a T-piece with the differential
> pressure measurement moved to between the 3rd leg of the T and the
> airbox. Run a pump, then both pumps, and see the lowest differential
> pressure the regulator can be expected to provide. If it is over 5 psi
> it is out of Rotax spec and the return line needs repair.
> It could be a very improvised connection - it should only have to deal
> with a gauge pressure of 5 psi.
> On the other hand, with a completely closed return line a pump delivers
> 1.8 bar (26 psi). And both in series 3.6 bar (53 psi).
> In that case you can make it a very short test.
> At zero pressure the pumps are rated to supply 120 l/h. I have heard
> that the pumps tend to get better with use. Maybe the improvement to
> your current 160 l/h is making it apparent that the return line is too
> restrictive.
>
> Regards,
> Jan de Jong
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