Lawn Mower?

You remove the High Tension (voltage) cap on the top of it - fit a Spark Plug Spanner - and unscrew it anti-clockwise.

Then you take a plug of the same type and work backwards through the process.

If the plug you take out is dirty with black soot you might think about cleaning it up - dry toothbrush - fine sandpaper -and resetting the gap.

http://www.youtube.com/watch?v=Iobn0fCun9k

Peccavi
November 2012