Jack Innes
Well-known member
This was just posted on another site & could relate to aftermarket carbs. being used on a T. The physics involved sound viable & it has been done with success.
I have a T with a Carter BB1 carb on it & will be checking the seat size.
Discovered this after years of fighting with my
BB-1 on my Overland. Suddenly I could drive on
the full fuel tank, not just the top 3 inches. The
Carter BB-1 came with either a #38 drill size seat
(designed for a pressure feed system) or a #31
drill size set (designed for a gravity feed system).
The larger #31 drill size opening in the seat is
around 40 percent larger cross-sectional area.
Now, with the greater force available from the
gravity feed head pressure, the horizontal
inlet needle can be pushed open and fuel will flow.
I didn't have a larger seat available, so mine was
opened up on a lathe using the #31 drill. I also
use a modern viton-tipped needle.
Hope this helps.
I have a T with a Carter BB1 carb on it & will be checking the seat size.
Discovered this after years of fighting with my
BB-1 on my Overland. Suddenly I could drive on
the full fuel tank, not just the top 3 inches. The
Carter BB-1 came with either a #38 drill size seat
(designed for a pressure feed system) or a #31
drill size set (designed for a gravity feed system).
The larger #31 drill size opening in the seat is
around 40 percent larger cross-sectional area.
Now, with the greater force available from the
gravity feed head pressure, the horizontal
inlet needle can be pushed open and fuel will flow.
I didn't have a larger seat available, so mine was
opened up on a lathe using the #31 drill. I also
use a modern viton-tipped needle.
Hope this helps.