Fuel filler cap size for 83 W/A

[eddielg]

fueled up today and the retention chain broke and the filler cap went splash.  Does anyone know what size and what type of threads were originally supplied on a 1983 W?A ?
Thank you,
Ed

[RickK]

I think I would measure the "hole" and then go to a West Marine and see what they have to fit.