take plug out and pop a little petrol down the bore, about a tee spoon, and then try and start. Does this make a differance? If it fires then dies I suspect a fuel problem. If it still does not start then it could be one of a number of things. Change Plug as well. Sometimes these can be dodgy. Do all th usual checks, oil, petrol etc etc
Post back and lets us know how you get on
bb
December 2009