How to Change a Lawn Mower Spark Plug
By: Julie Day
Step 4: Check Spark Plug Gap
Most spark plugs come preset to the proper spark gap, but you should check it with a spark plug gap gauge to make sure the gap is set to the distance recommended in your lawn mower manual.
If not, tap the end of the spark plug gently on a solid surface to reduce the gap, or bend it out slightly to increase it.