Gas
If there is gas left over from last season still in your gas tank it would be a very good idea to go ahead and empty that out into an authorized container and dispose of it in an environmentally safe way. Old gas, especially with ethanol in it will cause your equipment to run below its peak performance.
Air Filter
I would recommend changing it due to its low cost, most people leave their mower out in the weather and water will damage the ability of it to filter air effectively. If you choose to clean it make sure there are no rips tears in which dirt and debris can enter the engine.
Oil
Not only is it important to make sure you have the right amount of oil when running the equipment it is also just as important to make sure that oil gets changed on a regular schedule as it will over time lose its viscosity and collect debris from wearing internal parts and possible contaminants from the air and combustion. Change every season or every 30 hours of use, a small investment to take to ensure the longevity of your equipment.
Blades
Lastly, take a look at your blade or blades are they dull, rusty, all nicked up? All these things will cause damage to your grass and make your engine work harder to do the same job. Remember it’s just not about grinding down the blade you must ensure the blade is balanced after grinding in order to extend the longevity of your bearings and keep the engine from excessive vibration.
Hope these tips help you prepare your equipment for this new season.