As a first step, change the spark plug. If still nothing, is there any chance water has got into the fuel tank. Only takes a drop to block the main jet. Unscrew the float bowl retaining bolt and allow to drain.
Turn on fuel tap (if fitted) to purge fuel line.
Don't forget to hold the 'dead-man's handle'! (if fitted)
phil_saunders@bigfoot.com
Phil Saunders, September 2008