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Date: Tue, 21 Jun 2005 11:19:43 -0400
Subject: Re: [FlyRotary] EFI return fuel testing
From: Bulent Aliev <atlasyts@bellsouth.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Hi George, most of the injectors face down. I think if there are bubbles,
they will remain on top of the fuel rail and be returned back to the tank?
Buly

On 6/21/05 7:58 AM, "George Graham" <rx7ez@yahoo.com> wrote:

> 
> While running my ground testing, during the winters using auto
> fuel.  I used clear 3/8" tubing for fuel line, from my Facet
> pump up to my carburetor.
> 
> While the engine was producing power, I noticed bubbles in the
> line, on the pressure side.  Baffeled by how air could be
> leaking
> into a six psi line, I looked it over, and discovered that there
> was a slight kink in the tubing.  The bubbles were from the
> small restriction in the pressure line (come to think of it, it
> may have been a three psi pump, not six).
> 
> Anyway, the bubbles really don't bother the Carter carb, with
> a float, but, I wonder how much vapor bubbles are returned
> from the EFI pressure regulator.  It seems likely, that with
> a 35 psi pressure drop, the vapor may be very significant.
> 
> Certainly, someone on this list must have a setup capable of
> testing the theory.  All one would need would be a clear vessel
> to return the fuel to, and perhaps suck fuel out of, with the
> remaining system intact.  Pump on, engine off would seem the
> worst case.  Cold weather auto fuel would be the most likely
> to vaporize.
> 
> Test results could contribute to safe fuel system design.
> 
> 
> 
> George Graham
> Mazda Rx7ez N4449E
> Homepage <http://bfn.org/~ca266>