Spring Start up
I will usually change all the fuel filters in the fall and then I use to run the boat for a day or two, then change the plugs. BUT, if you can afford the money your engine should see a qualified mechanic once a year. Especially if your running any of the new technology out there. I now find myself doing my own winterizations on all three boats, but bring them to the Yamaha mechanic in the spring.
If you find a good company like I have at Nauset Marine, there bill has everything listed they did on the boat ,so there is no question on the billing. I find on average it is about $3-500 for the spring start up for a F225. There is a lot more to be done on todays motors than just plugs and filters. Remember, little things like your control cables need to be adjusted never mind idle control and valves (for the four strokes) and if your using the boats on the flats, like we do in Chatham, you MUST change your water pump every spring. With an initial investment of $18000 for a F225, that $500 bill once a year isn't looking to bad.
Stuff you can and should do.
fill and charge your batteries, clean all terminals on batteries and wires to those batteries with a wire brush. Check, no really, undo your bilge pump and make sure the paddle is free of debris and test your float switch and manual switch. Three miles out is not the time to find out your bilge pump only makes noise. Wash and wax your gel coat and wax more than once a year, if you can. $5000 for a paint job vs $10 for wax and 2 hrs time. If your boat bottom is painted sand and repaint to save on fuel. And last but not least GREASE the hell out of those fittings.
Happy boating and remember boating is not a cheap sport.