I changed boats this year. The new boat has a Yanmar 3JH5CE engine with saildrive. The handbook seems quite strict that only Quicksilver High Performance Gear Lube be used.
I have almost 5 litres of VolvoPentatransmissionoil left over from previous boat (also Yanmar3YM30 with saildrive).
What damage would it do if I used the VolvoPentaOil? Secondarily, does oil "go off" if I have it for a year unused?