I need a spare cap for my petrol tank on my boat so that I can modify one to add a vent and a flame arrestor and have another for show use or at sea (where I don't want to risk any water getting in my fuel in the event of a few waves). Does anyone recognise this type of cap and know a source of them, failing that does anyone know of any cap which might fit - the outside diameter of the threaded filler of the fuel tank is 2", I've got no idea what the thread is.
Thanks John