What is the benefit of using SAE 10W-40 oil in small engines?

Using SAE 10W-40 oil in small engines offers the benefit of better lubrication at high temperatures. This multi-grade oil is designed to perform effectively across a broad temperature range. The "10W" indicates that the oil has a viscosity grade of 10 at low temperatures, allowing for good flow during cold starts, while "40" represents its viscosity at higher temperatures, ensuring that it provides adequate lubrication and protection to engine components when the engine is running hot. This characteristic is especially critical for small engines that may operate under varying loads and temperatures, enhancing engine performance and longevity.

The other options may have certain merits in different contexts, but they do not specifically align with the primary advantage that SAE 10W-40 oil provides. For instance, cold start performance is more associated with the lower viscosity of the oil at lower temperatures, while longer oil change intervals relate more to the oil's additive package and overall stability rather than its viscosity grade alone.