Remove the fuel
So you don’t get fuel all through the engine as you flip the mower over to service it, remove any old fuel left in the tank. Turn the mower over and pour the fuel into a container.
Give it a clean
While you’ve got the mower on its side, clean out all the built-up grass and gunk under the body. If you leave it there, the airflow under your mower is disrupted so the clippings don’t go into the catcher as efficiently. This means you get clumps of cut grass left behind as you mow. Use a scraper to get off caked on dirt and a spray on degreaser for a final clean.
Sharpen the blades
Even the best mower isn’t going to cut well with a blunt set of blades. Unbolt the old blades and sharpen them using a bench grinder or metal file. If they have any nicks or chips from hitting stones, take them to the hardware store for a new set.
Clean the air filter
A clogged air filter will stop the air from getting into your engine so it won’t run smoothly. Depending on your mower, the filters are either paper or foam. Paper filters should be replaced, but you can clean foam filters. Give them a wash in warm soapy water, rinse then let them dry out. If you still can’t get it clean swap it over for a new one.
Be a bright spark
So the engine of your mower runs at its peak, swap over the spark plug. Clean around the plug before you remove it to stop any debris getting into your engine. Use a plug socket to pull out the old one and put the new one in. Be careful not to overtighten it.