Shields and Y pipes definitely getting replaced.
Its a good suggestion it could be coming from the cooling water, manifolds and risers were replaced in December. The mechanic has come to double check them too, so unlikely but I'll still have a look.
I trust the mechanic, he is experienced...
A few months ago I stepped up into a bigger boat, 32 foot with twin 5.7L Mercruisers. Had inspection and out of water survey etc.
The steering pin is corroding and replacement transom shields are on the list of repairs (allowed for in purchase price). I have also noticed some corrosion around...