I have exactly the same problem on my Woodbridge pro 20, but I run on lpg gas bottles most the time, only use petrol when bottle runs out or need more space on van.
It's been cutting out (occasionally) for about 6 months now,then it will run fine for a week, then cut out again!
Runs fine on LPG.
But before Xmas it got worse and now won't run properly on petrol (but it will tick over, then cuts out when revs increased).
Quite pleased that its got worse, should make it easier to find out what's wrong!!
Runs fine on LPG, so I manage anyway.
I think it's to do with the carb, going check it out soon.