Originally Posted by barry123400

If you can get one crankshaft turn by hand just change the oil and filter. Then let the engine spin by the starter with no glow plug for 10 seconds. I would remove the glow plug and drop a teaspoon of oil in there first. The initial 10 second spin up should circulate the oil to any dry points before any real load is applied. Install the glow plug and start it up.
If it starts up pretty easily and clean I would just shut it down after about a minute and wait till I was in the water to check the cooling circuit.
Check your alternator to make sure it is free before doing anything. Alternator brushes do stick sitting sometimes. Then check the water pump for leakage if you have coolant supply.
You may want to drain a little fuel into a container before you start anything to make sure it is clear and clean if he left any fuel in the tank. Or drain the fuel tank and look for water, dirt or growth in the fuel. Any dirt or junk in the tank will be shook up and cause trouble at some point. Better now to make sure the tank and fuel are clean. Also since the gentleman was older and had problems he may have forgotten to change the fuel filter out for several years. Unless it looks fairly new change it and make sure you have a spare or two. With a little luck they are already in the boat.
Lay the motor up properly in the fall. If you can introduce any lubrication to the water pump bearing now it might be a good ideal as well.