Start by tearing apart the carburetor and making sure its all cleaned out, especially so if you had been running regular ethanol type gasoline...One of the reasons we all stress to use nothing but ethanol-free gas in these 2 stroke beasts, change the spark plug out as well while your at it with an NGK-BR6HS spark plug.
Then we can go from there, but try this first since it is cheap and easy and probably the most obvious cause.
Ps...Hopefully your using only FRESH GAS, not some old crap thats just been sitting there.