I picked up this user report from the Tailwind discussion group.   I am
assuming the engine is an 0-320 as that is the usual choice for
Tailwinds.  I know several members of this list including myself are
considering the aero carb.   Buyer Beware...  Jerry

On my trip back from CA I decided to go to 11,500. I got good speeds
and fuel economy, however the carb started being finicky again. I
couldn't lean worth a darn and had to throttle back just to lean when
the engine was warm. Then I found when I landed at Saratoga, WY it
wouldn't shut down unless I turned the mags off or shut the fuel
off. Then on top of it all, it was leaking like a scive sitting on
the ramp if I didn't shut the fuel off.

Here is what I think. This carb is good for a VW, Jab, or
Continental. I believe the constant adjusting I have to do may be
partly because of the Lycoming engine design of being mounted on the
oil pan. I am thinking the carb body is getting hot and that is
causing the stuttering and vapor lock. The guys at Sonex fleetingly
talked about that but I could get no more info out of them. To make
things worse, I can't run ram air to the thing, so I am already
sucking in warm air into a warm unit. No problem with icing. I am
also not getting the RPM I want to get either-that may be part of the
problem.

My conclusion: I broke down and have a MA4SPA on the way.

-------------------------------------------------------------
This is only one half of the story Jerry.
I am going to contact Aero Carb before I publish this and get the other half.
It is the only fair thing to do.

Paul Lamar
----------------------------------------------------------------

Hello Paul-

Mark forwarded me your note for a company response. We appreciate the
opportunity to answer these kinds of posts and always will when and if given
the chance.

All of the issues detailed in this e-mail have a remedy with the AeroCarb
and it has everything to do with proper tuning. There is a section in the
AeroCarb manual that deals with Tuning that should be followed to obtain the
best fuel/air mixture for particular set-ups.

Not being able to lean the AeroCarb anymore is typically an indication that
you are too lean to begin with. The mixture valve on the AeroCarb is simply
a fuel valve at the fuel inlet of the carb. If it's running too rich at
altitude, you pull the mixture until it runs rough and then push it back in
until it smooths out. You then know you are running at the ideal fuel/air
mixture.

The AeroCarb Manual details the proper shut down procedure for the carb,
which is to pull the mixture control to full lean (cutoff). No more fuel
will flow and the engine will stop. This stops the flow of fuel so you won't
spill a drop.

If tuned properly in the first place by following the step-by-step procedure
in the manual, the AeroCarb will typically not need any other adjustment. We
have found that some customers do not take the time to read and understand
the manual, which leads to frustration downstream.

We've found in our many years of assisting our close to 1000 AeroCarb
Customers troubleshoot their installations that in most cases the Carburetor
they are blaming for their troubles is not the problem. Ignition Timing,
Fuel Delivery Pressure, Fuel Routing, Propeller Selection, and Manifold
Shape/Design are just some of the other items that must be considered when
troubleshooting why a particular engine is not producing expected power.
Note that many Aerocarbs have been installed and flown with great success on
the Lycoming Series.

There are only two adjustments required per year. Once in the fall as
temperatures begging to drop and air gets denser (1/4 needle turn rich) and
once in the spring as temps come back up and air becomes less dense (1/4
turn lean).

Ram Air can be run to the AeroCarb if you are sure to set-up at a rich run
on the ground. Once airborne, the Ram Air will serve to lean out the mixture
and some adjustments may have to be made on the ground for your particular
set-up.

Please feel free to contact Heather, Betty, John, Kerry, Mark, Jason,
Kristy, or myself at the numbers or e-mail below.

Regards,
jeremy

Jeremy Monnett CEO Sonex Aircraft,
LLC www.sonexaircraft.com
Tel (Info/Orders): 920.231.8297
Tel (Tech Line): 920.230.8324 Fax: 920.426.8333
E-mail: jeremy@sonexaircraft.com
Please use the following e-mails to Contact Sonex Aircraft:
Sales Info: sales@sonexaircraft.com
Orders: orders@sonexaircraft.com
Accounting: accounting@sonexaircraft.com
Tech Support: tech@sonexaircraft.com


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