I was kidding myself hoping that clearing all the oily grass had cured the frequent cut-outs.I used the Punch 35S today(15/6/09) and it was back to it's old tricks again.I noticed a regular drip of petrol from the float chamber so I cleaned the seal and reassembled it-leak fixed.However I still think Cledlyn's suspicion of the cut -out lead(Throttle control end) is the most likely culprit.I finished the last 20 mins. of mowing without a cut-out but if the problem returns the whole cut-out mechanism is in for a thorough sevice.
Terry Taylor- original question asker., June 2009