Boat owners have a large number of choices before them when it comes to buying an engine. There are lots of items to consider, including the boat's weight and the planned uses for your boat. (When calculating weight, be sure to also include the weight of passengers, cargo, and fuel, which can total hundreds of pounds.) If you build an engine with too much horsepower, it will drive up unnecessary fuel costs and possibly make the boat run faster than is safe. It should be noted, however, that too little horsepower is bad, too. The engine will run too hard and maintenance issues can multiply. Your boat's manufacturer should list solid recommendations on horsepower, however.

There are three basic kinds of marine engines and three types of fuel delivery systems. Engine types include outboard, inboard, and stern drive. Each has its own advantages, but the most common-at least for pleasure boats-is the stern drive engine. It involves an on board engine that drives the boat through a shaft powering the propeller beneath the craft.

The three types of fuel delivery systems are direct-fuel-injection, electronic fuel injection, and carbureted fuel systems. If being environmentally responsible is a priority, you might choose to avoid the two-stroke carbureted system. Although they are cheaper to purchase in the beginning and simplest to keep in running order, they are terrible polluters and they are definitely not known for fuel economy. They also have a high oil-to-gas ration, requiring 2.5 ounces of oil per gallon of fuel. Carbureted fuel systems do provide great acceleration, though, and lots of power. Pleasure boaters particularly like them for bass fishing and water skiing.

Direct-fuel-injection is more expensive up front, but it is cheaper to operate. Fuel goes directly to the cylinders for better fuel efficiency. Emissions are low, as well. They idle as smoothly as silk and are not given to vapor lock in warm weather. Similarly, electronic fuel injection offers low emissions and unvarying distribution of air and fuel. It offers great throttle response and regular cold engine starts.

Needless to say, there is much to ponder when looking at boat engines. The best advice is to know your boat's vital statistics and how much you want to spend. Investing in the highest quality engine you can afford and maintaining it without fail will insure you years of fun on the water.