Well. I just acquired the same model Flymo mower as the original poster ($25 off Craigslist) so I need to resurrect this thread, with some info and a question.
The mower has two air filters, a relatively normal foam filter, oval in shape, that goes in a housing attached to the carb. The second filter is a "snorkel" style filter, in a plastic canister attached to the mower handle, and connected to the oval filter housing via a flex tube and a plastic fitting. This uses a tubular metal / paper filter 6" long and 1.5" in diameter. I have tried to attach a pic, and hopefully that will come through OK. I don't see any part number on this filter, unfortunately.
So then the question, to the original poster - what carb rebuild kit was used, and where did you get it? Although I have spark, and the mower looks almost completely unused, I want to rebuild the carb before I try to run it. Thanks!
Flymo