You can't adjust the timing more than a couple of degrees either side of the correct setting. Try taking off the rubber between the carb and airbox and squirting some easystart in - if you can get it running like that its probably a carb fault. If not something more serious maybe.
If you get to the point of not wanting to bother any more I am looking to buy one!
Cheers, Paul 07753957427
Paul Jennings
September 2008