What type of fuel does a two-stroke outboard engine require?

Two-stroke outboard engines require a mixture of gasoline and oil as their fuel. This is essential because, unlike four-stroke engines that have a separate lubrication system, two-stroke engines utilize the fuel itself for lubrication. When the fuel mixture is drawn into the combustion chamber, it not only combusts to provide power but also coats internal components with oil, helping to reduce friction and wear.

Using a mixture of gasoline and oil ensures that the engine runs smoothly and efficiently while preventing damage from lack of lubrication. The specific ratio of gasoline to oil can vary depending on the manufacturer’s recommendations, but it is typically found in a 50:1 or 100:1 ratio for many modern engines.

In contrast, pure gasoline would lack the necessary lubrication for the moving parts in a two-stroke engine, leading to issues like increased wear or engine seizure. Gasoline mixed with ethanol, while commonly available in some regions, still does not provide the requisite oil for lubrication. Diesel fuel is not suitable for two-stroke engines since these engines operate on a spark ignition system rather than the compression ignition utilized by diesel engines. Thus, the correct answer reflects the unique operational needs of two-stroke outboard engines.