[timlyo]

Going through the example, it comes up with:

> Get that off of me before I catch on fire! > Needless variant. 'catch fire' is the preferred form

I don't think I've ever heard anyone say "catch fire" rather than "catch on fire".

From the UK if that changes anything.

[reikonomusha]

"To catch fire" is a relatively common term, at least in the USA. "To catch on fire" probably equally so.