Whether you're looking to buy a new motorboat or need to replace the motor on your current boat, you may be wondering how to choose an outboard motor. Outboard motors present a range of options, from two-stroke to four-stroke, and direct fuel injection to electronic fuel injection. Here are a few considerations to keep in mind as you select an outboard motor for your boat.

 

Should I Get a Four-Stroke or Two-Stroke Engine?

It used to be that a two-stroke engine was the go-to for outboard motors, according to Discover Boating. Traditionally, two-stroke engines have been lightweight and have had good throttle response, says Boats.com, while four-stroke engines have offered a cleaner, more refined performance. As environmental standards have changed and boaters look for a clean, efficient engine, Boats.com notes that modern outboard motors have evolved — narrowing the differences between four- and two-stroke engines.

Two-Stroke Engines

Two-stroke engines burn a mix of gasoline and oil, says Boating Magazine. In the past, a carburetor or injector fed the mixture into the engine cylinder through an intake valve. But, this led to a lot of fuel escaping, as the exhaust valve remained opened during this process. However, today’s two-stroke engines have been designed to prevent this loss of fuel.

Four-Stroke Engines

Four-stroke engines are similar to what your car would have, says Boating Magazine — they have cylinders that burn gasoline and a separate system to lubricate the engine with oil. Intake and exhaust take place at different times as the pistons move. Boats.com notes that this has historically meant that four-stroke engines don’t offer as much power as two-stroke engines. Modern fuel injection systems, however, have led to better fuel economy for four-stroke engines while manufacturers have upgraded the engines to be more powerful.

How Does Fuel Injection Work on Outboard Motors?

Manufacturers are now building outboard motors that are more fuel-efficient and low-emissions, says Discover Boating, thanks to modern fuel injection systems.

Direct Fuel Injection (DFI)

According to Boating Magazine, DFI two-stroke engines feed the fuel mixture into the cylinder while the piston covers this exhaust valve. This prevents the loss of fuel that occurred with older engines. DFI engines are available in both two-and four-stroke engines. They use less fuel, have increased engine power and have low emissions, says Discover Boating. They also don’t require fuel priming and are quick to start.

Electronic Fuel Injection (EFI)

With EFI engines, the fuel mixture is injected into each cylinder’s incoming air before it reaches the intake valve, says Discover Boating. The fuel spray then cools the intake valve, increasing vaporization before it reaches the combustion chamber. The fuel and air mixture is then ignited by a spark plug, says Discover Boating. EFI engines do not require fuel priming, and they have low emissions. They’re also quick to start and have lower fuel consumption without sacrificing performance, according to Discover Boating.

How Much Horsepower Do I Need for My Boat?

Simply put, it’s typically a good idea to get an outboard motor with the maximum horsepower recommended by your boat’s manufacturer, says Discover Boating. While more horsepower certainly means more speed, it will also help with handling at slower speeds or in rougher water.

Discover Boating suggests keeping in mind how you’ll be using the boat. While the test run may seem great, you may not be so thrilled with that smaller outboard motor when it’s more than just you and the dealer on the water. You’ll likely want something with more horsepower if you typically have multiple people on board, plan on water skiing or have lots of food and gear with you regularly.

Are There Electric Outboard Motors?

There are electric outboard motors available, and they may be a good fit for smaller boats or those who enjoy inland fishing, says Boats.com. Electric outboard motors are lightweight, very quiet and low-maintenance. You’ll likely need to replace the battery every few years, says Boats.com, but you’ll be saving on fuel costs, as electric outboard motors generally just need an overnight charge (which won’t likely run up your electric bill noticeably).

As outboard motor designs evolve, there are a lot of options available. With a little knowledge, you can be better prepared to choose the right outboard motor for your boat.