Gents,

Added to the Evangelista Torricelli explanations of the fuel tank.

In the past we did use bleed air carbs, without muffler.
These days we have our four strokes, also some times with the bleed air carburetor. As example the ENYA 60 4 C
I also did see a converted marine engine (OPS) with a carburetor on the backside of the engine.

For all these situations this post.

My advice is, in any case you cannot use muffler pressure , for sure not with a bleed air carb, mount the air inlet of the fuel tank near the air inlet of the carburetor.
As example the reference pressure measuring tube I use on the fuel pressure controllera on my glow engines these days.
(See also picture 4, Post 492 page 20)
The angle of the tube in the same direction as the air intake of the carb.
In the past I did mount the air intake of the fuel tank this way for my "old engine".

Doing this, the dynamic pressure of the airspeed on the carburetor you also have in the fuel tank, compensation is the best we can do, with any little pressure difference we can expect.
BTW, this also is a solution for the pusher engine. In that case we have probably a negative dynamic inlet pressure as result of airspeed, on both carburetor venturi and fuel tank.

In worst case situation, with a bad engineered air inlake for the fuel tank, we can have nearly the variations of twice the dynamic pressure of the air speed that influences the fuel flow so the fuel/air ratio of the engine.

More to come and if you have questions, ask!

BTW wood dust on the engine, MVVS, no problem.

Cees