Inspect and Change the Oil. Oil is the lifeblood of any engine, and snowmobiles are no exception. Even though snowmobiles aren’t used year-round, the oil still degrades over time. Make sure to:
Change the oil: Old oil can become thick and less effective at lubricating your engine. Replacing it with fresh, high-quality oil ensures proper engine performance.
Check the oil level: If you didn’t change the oil before storing the snowmobile, check the oil level and top it off as necessary.

Check the Fuel System. Fuel can break down or go stale when left sitting for too long. This can lead to clogging and poor engine performance. To keep your fuel system running smoothly.
Drain old fuel: If you stored your snowmobile with old gas in the tank, it’s a good idea to drain it and refill it with fresh fuel.
Add fuel stabilizer: If you didn’t drain the gas at the end of last season, adding a fuel stabilizer to the tank can help prevent issues with the carburetor or injectors.
Check the fuel lines: Inspect the fuel lines for cracks or wear. Over time, rubber can deteriorate and cause leaks, which are dangerous.

Inspect the Spark Plugs. Spark plugs ignite the fuel in the engine, and worn-out plugs can lead to poor performance, rough idling, or difficulty starting. Be sure to:
Check for wear: Look for signs of corrosion or deposits on the spark plugs.
Clean or replace: If the plugs look worn or dirty, clean them or replace them entirely to ensure a strong spark.

Examine the Battery. Snowmobile batteries often lose charge or degrade when not in use for extended periods. Before you head out, check your battery’s health by:
Testing the battery: Use a multimeter to check the voltage. If the battery is weak, recharge it or replace it with a new one.
Cleaning the terminals: Battery terminals can corrode, leading to poor connections. Clean the terminals and apply a thin layer of dielectric grease to prevent further corrosion.