What type of oil should NOT be used in a two-stroke engine?

In a two-stroke engine, the type of oil used is critical for ensuring optimal performance and longevity. Multi-viscosity oils are designed to perform well under a wide range of temperatures. However, they may not provide the necessary lubrication properties that a two-stroke engine requires, especially when mixed with fuel. Two-stroke engines typically function best with oils specifically formulated for their design, as these oils ensure proper combustion and lubrication.

Using oils not intended for two-stroke engines, such as multi-viscosity oils, can lead to incomplete combustion, increased smoke, and the potential for engine wear due to inadequate lubrication. In contrast, oils specifically formulated for two-stroke applications, such as two-cycle oil with the proper rating, are designed to combust fully and provide effective lubrication to the engine components, thus preventing excessive wear and maintaining engine efficiency.