I still like mechanical fuel systems as they are inherently simpler to understand,
very reliable with one or two moving parts and easier to diagnose and fix.
EFI is over kill for an aircraft engine. You don't need super accurate mixture
control as the engine will run anywhere between about 9:1 and 18:1 air fuel
mixture. Starts best at full rich. Best power at 12.5:1. Best economy at 18:1.
Once you are established in cruise you can set the mixture to whatever.

To illustrate just how simple mechanical fuel systems can be and still work here is
a picture of the Wright Brothers engine. The four things on the top are
spring loaded intake valves. They open automatically when the piston is on the
down intake stroke due to vacuum in the cylinder. Below them is a rectangular tray.
Thats it!!! No intake manifold, no fuel pumps, no air throttle, no anything except a
gravity feed fuel tank and a petcock. The pilot opened and closed the petcock
as needed to keep the engine running while the fuel dripped on the tray out
of the petcock. The warm tray vaporised the fuel.

BTW There was no high voltage ignition system, distributor or spark plugs either.
There was a set of contacs inside the cylinder with battery voltage across
them that sparked when they where forced open or closed (I forgot which)
by the piston rising in the cylinder.
-- 
Paul Lamar ...No rotor no motor.

Not much power either :-)
Bill Schertz
KIS Cruiser #4045

12 HP. The really amazing thing about the Wright brothers was they
were excellent engineers. As far as I know completely self taught.
They must have read everything they could find on a lot of engineering subjects.
Even today it is no easy task to design an airplane that will
fly on 12 HP let alone design your own engine. The main thing they had
going for them was the two large diameter props. Those props must have
been near optimum designs to provide the low speed thrust needed to
fly on only 12 HP.

BTW Bill you must be getting pretty close to flying. How is it going?