Westwood T1200 not starting from the pull?

Hi, My T1200 doesn't want to start from the pull cord. It stopped on me whilst cutting, I got it restarted then lowered the cutting deck and it stopped again, I have not been able to get it going since. Checked spark plug and replaced it, could also smell petrol when spark plug taken out so fuel ok. I'm thinking it could be an electrical problem but don't know where to start, any ideas???
Thanks in advance.