Check engine for its WOT wide open throttle.
Check operating temp, use a handheld IR sensor to verify helm gauge, also measure exhaust manifolds and risers. All should not exceed 175.
Check outdive lube for signs of water and corrosion.
Check transom and stringers for rot by hitting with a dead blow hammer listening to hollow sounds.
What model are you looking at and what engine?
1997 2400 SCR
5.7 Vortec / Bravo 2