What oil goes in British Seagull outboard motor gearcase?

Earlier models require 90 wt. and newer models 140wt. More important however is to use only API GL1 rated oil, regardless of weight. GL1 contains no sulphur-based high pressure additives. These additives will cause severe corrosion of the Seagulls bronze/brass lower end bearings/bushings. GL1 is still used in old car transmissions and is common in the food processing and timber/lumber industries.