Whether you just bought a new motor, or are looking for ways to extend the life of your current motor, there are a few simple tips and tricks that will be extremely beneficial. When looking to improve your motor's performance, you need to consider four different areas of the engine: the fuel system, the cooling system, the ignition system, and the lower unit.
To maintain your fuel system, the first thing you must do is check your water-separator primary filter for water accumulation and rust or dirt. Get rid of any water or debris in the fuel tanks and check all hose connectors for deterioration and gunk. According to Boatkeeper, using only clean TC-W III oil and checking the carburetors for leaks will increase the life of your motor significantly.
Once you have run through your fueling system, you need to address the cooling system. Observing the telltale stream for signs of cooling pump failure (if the stream is weak or nonexistent) will tell you if you have trash or sand clogging the water pump impeller. In addition to checking the health of the water pump, it is critical that you flush the engine after every outing. This applies to both freshwater and saltwater outings. To flush out your motor you will need a set of "rabbit ears". These are two flexible rubber seals connected by a rubber clamp that slip onto the lower unit where the water is picked up. You can then attach a garden hose and start the engine. Boatsafe.com reports that you will only need to run the engine for 10-15 minutes to ensure a proper flushing.
Your ignition system is fairly easy to maintain as the only important components are the spark plugs, caps and wires. Spark plugs should be checked occasionally as they wear down quite a bit with use. Clean them often with a wire brush and make sure to keep a spare set in your toolkit. Wires and caps should also be checked for fraying and corrosion.
Finally, the lower unit of your outboard motor should be checked for looseness or unsteadiness at the prop shaft. The oil should be changed after every season, and especially if you find dirt, metal, or debris in it. Doing a quick check before every outing can help prevent small problems from becoming bigger ones. If you do not feel comfortable performing huge repairs, you can always take your engine to an outboard services store like Rick's Master Marine to have it assessed.