It’s hard being a boat engine! Unlike its automotive cousins, a boat engine is run at extremely high RPM’s and under quite a load when in operation and it sits in storage a whole lot of the time. It’s kind of the worst of both worlds. Today’s marine engines are very well made and unlike their predecessors, really experience very few mechanical problems if they are properly maintained.

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, I’m 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 boat’s 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.

Electronic Control Module – Most modern marine engines are controlled by a computer call an ‘Electronic Control Module’ (ECM) which regulates the flow of fuel and air as well as the timing of the ignition system. Another valuable function of the ECM is that it stores operational data while the engine is running. Certified marine mechanics have digital diagnostic tools which can be connected to the ECM to learn the running history of the engines as well as any problems.

Anodes On the underwater section of every outdrive and outboard engine, there are one or more little metal attachments called ‘anodes’. They are usually made of zinc and are designed to attract stray electrolysis. This occurs when stray voltage in the electric system of a boat is transmitted through the metal parts of the boat in search of a ground. The anodes are designed to be sacrificial and to absorb the stray current and gradually deteriorate. This process is magnified in salt water. At least once a year, you should check your anodes for decay and replace those that appear to have decayed greatly. Replacement anodes are not tremendously expensive and they serve to protect your boat from some serious decay of some very expensive metal marine parts.

If a marine engine is properly maintained, it should give you many years of trouble free operation. It should be important to you to know a qualified marine technician in your area. As with most things, “An ounce of prevention is worth a pound of cure”. Have a great cruise!