Wow! Thanks for all the info!!
I'd better reiterate that the mower in the pic isn't mine. What you said about the governor makes sense though. It seems like the cutout wont reach the plug either, it's probably redundant.
I'll get some pics once it's back together.
The guy I bought it off said it stopped running. I'm guessing its just a dirty carb and old fuel. Anything else on this sort of engine that would stop it running?