[SEL] Attention Aussies - Austral Question

[fero_ah at city-net.com]

Hi Folks,

Down at Zolfo Springs Dave and I were puzzling over the details of exactly how
the vaporizer works on his 11 hp Austral oil engine.  After a bit of RTFM, I
think I have most of it sussed, but there's a couple of bits that just aren't
clear.  I wanted to take a wrench to it and have a look at the innards, but
Dave was having none of that.  So I'm forced to ask y'all for some help.

Here's the engine in question...
http://www.oldengine.org/members/arnie/Zolfo_2007/Austral.jpg

And here's a look at the vaporizer with the outer heat shield removed.
http://www.oldengine.org/members/arnie/Zolfo_2007/Vaporizer.jpg

During the intake stroke, the timing valve is open to the combustion chamber,
the vapor valve opens and a mix of atomized kero and air is drawn in from the
mixer.  The kero is vaporized and passes through the open timing valve where it
enters the combustion chamber with the main air charge from the open intake
valve.  The timing valve closes.

At a point into the compression stroke, the timing valve again opens allowing a
compressed air - kero vapor mixture to enter the vaporizer and reach the hot
ignitor coil, where it ignites.  The timing valve remains open allowing the
burning mixture to heat the vaporizer and the ignition coil during the power
stroke.

I think the reason that the initial air/kero draw doesn't ignite on the ignitor
coil is that the mixture is way too rich.  But it's equally possible that
internal baffling and/or residual exhaust gasses around the ignitor coil help
to prevent ignition until a suitable mixture gets compressed into the
vaporizer.

Finally, the shape of that vaporizer body looks like it ought to have something
to do with the internal geometry.

Can anyone shed more light on the internal geometry and functioning of that
Austral vaporizer?  It sure is one sweet running engine and it would be really
great if Dave and I could do a better job of explaining just how it works.

THANKS!!

See ya,  Arnie

Arnie Fero
Pittsburgh, PA
(from warm & sunny Zolfo Springs)