Ken Welter has been flying a Weber for a few years on his Coot. I
   think he
   is tricking the float chamber by using dynamic air pressure to lower the
   fuel level.
   I am not sure. I don't fully understand what he is doing. Perhaps
   that is
   possible with a needle valve.

   Paul Lamar ...No rotor no motor.

   It was my understanding that (for flying or Pikes Peak) the Weber is
   jetted
   with the choke on then as you climb you lean by backing off the
   choke.  I
   wonder up to what alt. that works to.
   Ernesto

The Weber uses a accelerator pump jet. The carb will pull through that
jet at low altitudes & WOT. Similar to the Holley power-valve. At high
alts. there wouldn't be vacuum enough to draw through that jet. Mild
automatic leaning. The Weber is a complicated device. It won't be easy
to duplicate, even just one circuit. My bet would be that when finished
the duplicate would cost twice as much as the original. You can't make
10 parts and get any economies of scale. There are at least 10 tunable
circuits on a Weber. They wouldn't make the carb that complicated if
they could do it simpler. I think it would be folly to go into the task
of making a carb. Buying a available unit is a vastly safer course. I
understand why everyone would like to make a custom unit. It may work, I
just don't think it would be cost effective. As much as everyone has had
some difficulties getting started I really believe Tracy's unit or
another EFI will end up being the easiest in the long run. If not that
buy a standard carb, and adapt a electronic ignition. My $.02 worth.
Bill Jepson


Bill there is a world of difference in the operation of  a car and
an airplane engine. I am not trying to duplicate a Weber.

I'll be happy with the mixture anywhere in the range of 10:1 to 20:1.
The AC engine runs at constant RPM and load for 99% of the time.
The pilot sets the mixture as needed.

Klaus ran his engine with a small hole into the intake manifold connected
to a gravity feed tank. No venturi. No other parts. Nada. Nothing.

Klause has also tried EFI. He took it off. He gets 50 MPG at 180 MPH
with a carb. He went 254 MPH in the Dayton to OSH 500 mile race with
a carb.

Many people have had trouble with EFI. Its not worth it. 99% of the airplanes
out there have trouble free carbs and every mechanic knows how to work
on them.

Paul Lamar ...No rotor no motor.

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