What type of fuel line is commonly used in modern small gas engines?

Low-permeation fuel lines are designed to minimize the loss of fuel vapors, making them highly effective for modern small gas engines. These engines increasingly utilize gasoline with ethanol and other blended fuels, which can be more aggressive on fuel line materials. Low-permeation lines are made from advanced materials that not only reduce the chance of fuel leaks but also help maintain the quality of the fuel over time by preventing evaporation and degradation.

In contrast, the other materials mentioned may not hold up as well against the newer fuel formulations. Rubber lines, for example, may be more susceptible to degradation and might allow more vapors to escape, leading to inefficiencies and potential environmental concerns. Viton, while resistant to certain chemicals, is often not as practical for general fuel line applications due to cost and availability. Single-layer fuel lines also do not provide the same level of vapor containment compared to low-permeation designs, which integrate multiple layers and specialized materials to enhance performance and durability in the face of modern fuel challenges.