183.526—Carburetors.
(b)
Each carburetor must not leak more than five cubic centimeters of fuel in 30 seconds when:
(1)
The float valve is open;
(2)
The carburetor is at half throttle; and
(3)
The engine is cranked without starting; or
(4)
The fuel pump is delivering the maximum pressure specified by its manufacturer.
(c)
Each updraft and horizontal draft carburetor must have a device that:
(1)
Collects and holds fuel that flows out of the carburetor venturi section toward the air intake;
(2)
Prevents collected fuel from being carried out of the carburetor assembly by the shock wave of a backfire or by reverse air flow; and
(3)
Returns collected fuel to the engine induction system after the engine starts,
Code of Federal Regulations
[CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by CGD 77-98, 42 FR 36253, July 14, 1977]