On the v drive check the oil colour before /during - changing.
It should be red and nothing else.
On the engine check the oil colour smell and feel. Very gross tests I know.. but will let you know if something big is imminent.
Then fluids filters and belts...
Some things to note.. check the timing belt/chain.
out the heat exchanger core
Check the engine mounts.
Have a close look at the block water
pump.. check for seeps.
Check the state of the water
pump">raw water pump impeller and check for corrosion
Check the prop seal and shaft bolts.
Check the exhaust color... Rich lean.. adjust as appropriate.
The use it some... And repeat!
The users manual has the maintenance