How do you change oil on 1977 John Deere 300 snowmobile?

To change the oil on a 1977 JOHN DEERe 300 snowmobile, first, warm up the engine slightly to thin the oil for easier drainage. Next, locate the oil drain plug underneath the engine and remove it to let the old oil flow out into a suitable container. After the oil has fully drained, replace the drain plug, and refill the engine with the appropriate type and amount of new oil through the oil fill cap. Finally, check the oil level with the dipstick to ensure it's within the recommended range.