Yamaha 30 hp gear box water issue

[The Johnsons]

Hi there my father in law has just replaced bearings and seals into my second hand Yamaha 30 hp 3 cylinder gear box and its getting water into gear oil we have no idea where its coming from.
Can anyone out there give us any ideas?

[rodbolt17]

propshaft bearing carrier oring,propshaft seals,driveshaft seals,seal carrier oring/gasket,shift shaft seals or the drain and fill washers.