What type of snowmobile engine is known for being cleaner and quieter?

The four-stroke engine is known for being cleaner and quieter compared to other types of engines, such as two-stroke engines. This is primarily due to its design and operating principles. In a four-stroke engine, the combustion process is more complete, which leads to lower emissions of harmful pollutants. Additionally, four-stroke engines often utilize a more complex valvetrain that allows for better airflow and fuel efficiency, further minimizing the environmental impact.

Moreover, four-stroke engines generally operate at lower RPMs compared to two-stroke engines, which contributes to quieter operation. The design features of a four-stroke engine, including a separate lubrication system, also help reduce the amount of oil burned along with the fuel, resulting in less smoke and noise. This makes four-stroke engines a preferred choice for users looking for a cleaner and quieter snowmobile experience.