Outboard Motor Types Explained

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The decision to buy a boat is an exciting one, and even if it's just a small vessel, your options for leisure and entertaining friends will be completely transformed. You'll probably want to use every spare moment to get out on the water, whether that water takes the form of the sea, a lake, or a river. If you're one of those incredibly lucky people who live near all three, you'll find it even more difficult to resist boating.

When you've got a few specific boats in mind, you should look more deeply into their features and condition. One of the things you'll want to consider is the type of motor the boat has. Many small boats have outboard motors, which sit mostly on the outside of the body, but these are divided into three different types, so you should get to know them before making a decision.

Two-stroke engine

The 'strokes' in the name of a motor type refer to up and down piston movements. A two-stroke engine completes one set of up-down movements in a single revolution, and as a type of motor, has been used for quite some time. What this means is that their construction is fairly straightforward, and they power boats efficiently. However, you should expect a higher rate of emissions than a four-stroke engine, which some people find off-putting.

Because they're light, compact and hard-working, two-stroke engines are widely used on small boats, but their fuel efficiency isn't the best.

Direct injection engine

A type of two-stroke engine, a direct injection motor differs in the way the fuel is processed. With a direct injection engine, the fuel goes directly into the combustion chamber, which makes consumption a bit lower, as it's a more efficient method.

It's a more modern method of powering the boat, and sometimes these engines are connected to computers which help them operate. In addition to reduced fuel consumption, this type of engine also has lower emissions.

Four-stroke engine

A four-stroke outboard motor has additional steps for each revolution. The four strokes are intake, compression, combustion and exhaust, and the process takes slightly longer than a two-stroke operation. Like direct injection engines, you may find a four-stroke connected to a computer.

Although they're larger, heavier and a little slower, four-stroke outboard motors have low emissions and excellent fuel efficiency. However, they won't get your boat moving as quickly as a two-stroke will. That's not a problem for some people, though, and a leisurely boat ride may be far nicer with lower emissions.