A lawn mower can last you for many years if you keep up on the maintenance. If your lawn mower has recently begun to have difficulty turning over, the problem may be found in the spark plugs. If the spark plug on your lawn mower is worn out and dirty it can prevent a spark from occurring. This will prevent the lawn mower from starting. In this case you will want to remove, clean and change the spark plugs on your lawn mower.
Step 1: Remove the Spark Plug
It is impossible to clean a spark plug while it is still attached to the lawn mower. Most lawn mowers will only have one spark plug to worry about but there are some models that will have more than one. If this is what you are facing, remove and clean each spark plug one at a time as they are in a specific order.
Your spark plug will be visible from the outside of the lawn mower unless you have a riding mower in which case you will have to lift the hood as you would on a car. Once you locate the spark plug remove the black wire attached to it as well as the cap covering the end of the spark plug. Use your wrench to remove the spark plug by turning it to the left. If the spark plug is very dirty and stuck fast, you may need to use a set of pliers in order to get enough leverage to loosen it.
Step 2: Cleaning the Spark Plugs
When you have the spark plug removed look closely at it for signs of dirt, grime or corrosion. If you happen to find a white substance that is oily to the touch, you have a fuel leak problem; otherwise dirt is normal. Spray the spark plug with the brake cleaner and allow it to sit for a few minutes. The cleaner will penetrate the particles of the dirt making the spark plug easier to clean. Use a wire brush to gently scrub the metal threads of the spark plug taking special note of the tip. Spray the brake cleaner on the spark plug again to remove any particles that you loosened up with the wire brush. Repeat this process as many times as you need to in order to remove as much dirt as possible from the contact point and threads.
Step 3: Finishing Up
When you are completely satisfied that all the dirt is removed or, at the very least, as much as you can remove, you can now buff the spark plug. Gently use the soft cloth to wipe off any cleaner residue that may remain. Now, with a little elbow grease, rub the metal of the spark plug until it is completely dry and the metal shines. The use of more brake cleaner may be applied. When you are completely satisfied you may replace the spark plug and all the wires.