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Water Pump Maintenance - Most marine engines are cooled by their pumping of lake or ocean water into the engine from a pickup in the lower unit of the outdrive or outboard engine. This water is circulated by a water pump that contains a rubber or plastic impeller or fan which pulls the water from the lake and pumps it up and through the water jacket of the engine to keep things cool. As you might expect, there are sometimes impurities in the water or the operator (somebody else, Im sure) that runs the lower unit aground and the impeller picks up sand, dirt or other grit. These foreign substances wear on the impeller and sometimes cause it to shred into pieces and fail. Also, if the engine is stored for a period of many months, sometimes the rubber of the impeller gets brittle and cracks up. In any event, it is simply a good idea to proactively replace the impeller every 3-4 boating seasons. If the impeller fails while you are running and you fail to notice the temperature rising, your engine can easily and quickly overheat and self destruct.
Oil Change Marine engines are typically not run more than 60-80 hours per year and, therefore, do not require oil changes very frequently. Usually, it is a good idea to change the oil (and filter) once per year at the end of the season. If the old, dirty oil is in the crankcase when the engine is stored in the off season, it can turn acid and damage the internal engine components it is supposed to protect. Of course, 2 stroke outboards have no crankcase and therefore no oil to change. On these applications, it certainly does pay to stabilize any fuel remaining in the tank and to fog the engine with fogging oil before storage.
Fuel Injectors Most newer marine engines are fuel injected and, when fuel is permitted to age and thicken during storage, the fuel injectors can easily become clogged and may fail at the start of the season. To avoid this occurrence, it is a good idea to run some fuel injector cleaner mixed into the last tank of fuel before the engine is put up for storage.
Battery If you take care of your boats battery, it will provide you with several years of good service. You should take care whenever you complete a voyage to ensure that all electrical components are turned off and, if you have a main battery switch, be certain that it is turned off. Whenever the boat is stored for any prolonged period of time, the battery cables should be disconnected.
Lower Unit Lubrication The lower part of your outdrive or outboard engine is filled with a lubricant fluid that keeps all of the moving parts properly lubricated and running smoothly. The reservoir should never contain any water in the fluid. The drive should be inspected at least annually to ensure that the drive is full of fluid and that no water is present. This is relatively simple and inexpensive to accomplish.
