Before it is time to take your boat out on the water, there is some maintenance that needs to be done. You should clean it, top to bottom, including the engine and all the parts. Inspect the fuel system for any leaks, and check all hoses, belts, and cables to ensure they have not dry-rotted or cracked over the winter. Change the oil and filter and top off all other fluids. You should also check all electrical connections for any corrosion and clean them off before starting the engine. Take inventory of the spare parts you have on hand, and be sure to make note of what you need to pick up while getting the normal maintenance stuff. Here are a few marine maintenance parts you should always keep in supply.
Unless you plan on rowing back to port if the propeller is dented or damaged while you are out and about, you should keep a spare propeller on hand at all times. It would be a good idea to also have a spare hub. Before you head out, make sure the propeller wrench is on the boat and not back at the dock.
Impeller and Pump
You should have a spare impeller for every pump on the boat. It can be easier to change an impeller than the whole pump. Of course, having a spare pump is always a good idea too. Sometimes just swapping out the impeller is not going to fix things. You don't want water to fill the boat or engine compartment.
Keep enough extra of each fluid for a complete fill. This will include oil, coolant, transmission fluid, and lubricants. If the component has a filter, be sure to have a spare of that, too. Be sure to use caution and common sense when changing or adding any fluid. You do not want to end up releasing anything into the water that could harm the flora or fauna there.
If you only have one engine and you have the storage space, you may want to consider keeping a spare on hand. Of course, you should consider where you will be boating and how far you may get from shore. The further out you will be, the more spare parts you should take with you. A blow-up raft is always a good idea to have too. Of course, when all else fails, you can contact the Coast Guard for a tow.
To learn more, contact a marine maintenance parts supply store.