Can i use 80w -90 oil on lawn mower?

Yes, you can use 80W-90 oil in a lawn mower, but only if it's specified for use in the mower's gear or transmission system. Typically, lawn mowers require lighter oils, such as SAE 30 or 10W-30, for the engine. Always check the owner's manual for your specific mower to ensure you're using the correct type of oil for optimal performance and to avoid potential damage.