That old Suzuki would be Autolube when built, but who knows now.
It looks about the right size for the boat to me, but I don't really get the concept of an engine being too big
I do understand that an engine can be too small, and that's really bad.
I'm a bit of a fan of the bigger 90's Suzukis, but many are not. it will be thirsty, and have electrical issues from corroded connectors, but it's all fixable.
You do need to find out if it's been flushed properly otherwise it will have waterways full of salts.
The boat is a well respected boat, but others on here will know more.
I'd be tempted by it for the price, but plan to change the engine within the next few years.