Petrol mower in very good used condition, being sold as repairs or parts as won't start, was working fine then ran out of fuel so pushed it in shed then when I refuelled it won't start?

There's a spark at plug and also petrol getting to spark plug will fire but not start, and I've had enough of pulling to start so will pass it on to next owner to fix, can't be a lot wrong and would be a easy fix to the right person, buyer collects or maybe able to deliver locally at added cost