Replace belts and hoses that show signs of wear immediately. It's also a good idea to carry spares for emergencies. Fully Charge the Batteries Batteries provide most of the electric power on boats. But, the most important component the battery powers is also the one which draws the most power-the engine starter. If not properly maintained, batteries can quickly discharge and leave you stranded.
Most stern drives have at least one anode attached to the exterior of the lower unit.
Other anodes are attached to the engine so they protrude into the cooling system. The proper amount of zinc attached to a boat is extremely important. Not using enough zinc will cause more rapid deterioration of the metal parts of your boat you are trying to protect. If in doubt, it is far better to replace the zinc than to replace expensive metal parts. The majority of stern-drive equipped boats use a raw water cooling system to cool the engine and stern drive unit.