When you take your lawn mower out of winter storage in the spring, be sure to follow these steps:
Give the body and engine a once-over, looking for loose bolts, missing or loose parts and fluid leaks.
Check the blades for wear and damage, and make sure the bolts that hold the blade in place are tight. If the blade is dull or damaged, take the mower to a repair shop or mower dealer for sharpening or replacement.
Check the air filter, the foam pre-cleaner and the paper element cleaner. If necessary, clean the foam element. If the foam element requires oil, use clean engine oil and only apply enough to wet the foam. If the paper element is excessively dirty, be sure to replace it.
Check the oil. Remove the dipstick, wipe the oil from it, and insert it back into the engine, without screwing it in. Then remove the dipstick and check the oil level. Add oil if necessary. Your owner’s manual should specify a type of oil. Oil should be changed once per season. If you changed the oil before storing the equipment for the winter, another oil change is not necessary until next fall.
Check the lawnmower bag, if it has one. Clean the bag according to the owner’s manual instructions, and replace it if it is worn, torn or clogged.
Over the course of the season, keep an eye on the grass to monitor the sharpness of your mower blade. If the clippings have clean cut edges, your blade is likely in good condition. If the clippings have ragged edges, take a close look at the mower blade because there's a good chance it has dulled.