Fuel line
Fuel line means hose or tubing designed to contain liquid fuel (including molded hose or tubing). This does not include any of the following:
(1) Fuel tank vent lines.
(2) Segments of hose or tubing whose external surface is normally exposed to liquid fuel inside the fuel tank.
(3) Hose or tubing designed to return unused fuel from the carburetor to the fuel tank for handheld engines.
(4) Primer bulbs that contain liquid fuel only for priming the engine before starting.
Source
40 CFR § 1054.801
Scoping language
The following definitions apply to this part. The definitions apply to all subparts unless we note otherwise. All undefined terms have the meaning the Clean Air Act gives to them. The definitions follow: