Hi all and esp Blumbly,
Don't know this model mower but the 2-stroke engine sure looks like the Villiers I remember from our Rover Princess when I was young in the 70's.
In which case I can tell you our fuel cap was metal (no. 96 in Cyberjack's diagram) and painted the same bright orange as the tank. Underneath it was a small plastic shield which we were always careful to replace (no. 134- I think- in the diagram). The plastic shield had a lip to fit over the rim of the lid's thread so you had to make sure you didn't screw it down too tight. If I remeber rightly, you could also drop the plastic lid down into the tank if not careful, a real annoying job to get out (but aided by little-boy fingers, a piece of wire and an annoyed father at the time). Both items had a small pinhole for ventilation, if I remeber rightly the cap pinhole was in the centre and the plastic shield pinhole was offset. The best way was to fit the plastic shield into the back of the cap and then screw it on, to prevent it catching on the thread and being chewed up. Forgive me for a dimming memory, this was up to 35 years ago now...
Just my 2c worth (which rounds down to zero nowadays of course
)
Pitrack_1P.S. Oh and I think the metal cap had a thin band of vertical lines/ridges around the top rim for grip (bit like the edge of a silver Oz coin e.g. 20c piece).
