Thanks guys,
yep it's the vertical pull start model. Turns out the kill wire was earthing out somewhere. Gave it all a good clean and put it back together and we have spark again

Starts fine and runs pretty well, it does have a bit of a miss every 30 seconds or so or sometime more frequently. I had another briggs that did much the same thing.
It's not really a big deal but is there anything I can do about it?
Cheers