Tipped out last years petrol, put in fresh from the petrol station. Fuel runs from the tank to the carb, i've taken the carb bowl off, opened the tap and it pees out. The carb is also clean as a whistle. There is also a decent spark. Air filter is clean and tube to carb is clear.
Pull cord and it starts, runs absolutely fine for 15- 30 seconds and then dies in a manner that suggests fuel starvation ie it doesn't cough and splutter, just gives up. It then won't start again straight away but if you leave for a while (half hour at a guess) then it will start and run for the short period of time again.
Nothing has been altered on it since last mowing season and it ran fine then.
It is driving me nuts! And no i can't cut my grass in 15 second intervals