Try changing the fuel just in case, though a month old should be OK. Try tossing fuel direct into the cylinder. With no choke if it runs for more than a split second you've probably got a fuel problem. I've got an old Canadien 26" and it only starts this way but keeps running till the tank runs out. It's so heavy that this is quite long enough. Have a look into the air inlet and the exhaust so make sure they are not blocked. Wasps tend to make nests in these areas which will give you the symptoms you've got.
Then again it's a good excuse ti get a new one. :):)
My two bobs worth, hope it helps.
Deano

