The Do's and Don'ts of Buying a Boat Engine

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The Do's and Don'ts of Buying a Boat Engine

Buying a boat, for many people, is a major step towards living a dream lifestyle. Boats have many advantages, including one that may go largely unnoticed: it is relatively easy to remove or install an outboard boat engine. Unlike a car, boat engines are designed to be removed for service or inspection. For this reason, it is possible for boat owners to easily upgrade to a newer, more powerful engine, or to replace one that has become damaged or otherwise unusable.

Once a person thinks it through, it is actually easier to replace a boat engine as opposed to a car's engine. There are some things that should be done, as well as some things that should be avoided, when making a purchase as critical as a boat engine. These do's and don'ts relate to choosing engine size, type, and fuel considerations. Understanding all of these factors can make it possible for any boat owner to buy with confidence, regardless of whether the engine is being purchased in a boating store, or online via eBay.

Do Choose The Right Engine Size

Engine size is important to decide before making a purchase. Size does not necessarily refer to physical volume. Rather, it usually refers to weight and horsepower. Engine weight, especially in relation to the weight and size of the boat, can be a major factor in boat speed, fuel efficiency, and how frequently the engine needs to be repaired.

Horsepower Ratings

It is important to look at horsepower ratings for each boat. Boats are designed to be used with engines within a certain horsepower range, determined by a rating. Each boat should have a rating designated by the manufacturer that can be found either on the boat, or in the owner's manual. It is also possible to find horsepower ratings online. These ratings are generally determined by the boat's weight and shape, and usually mean that the engine may not be the right size for the boat. It is generally advisable to come as close as possible to the maximum horsepower rating in order to find the best fit. With the rating in hand, it is possible to find an engine that should not overpower, or underpower a boat.

Horsepower Range

Weight (kg)









While more powerful engines typically weigh more, they also provide much greater power. It is also important to note that a heavier engine makes transporting the engine more difficult. If the boat is too heavy for the engine, the engine pushes harder, causing more fuel consumption, and may require more frequent maintenance. At the same time, a heavy, sluggish boat with a weak engine cannot perform as well, and may in fact reduce overall enjoyment.

Do Understand the Difference Between Inboard and Outboard Motors

In terms of what type of engine to choose, boat owners have two options. Most boats are equipped to use either an outboard motor or an inboard motor. Outboard motors, as the name implies, are placed on the edge of a boat with the bulk of the engine actually kept outside of the boat. Inboard engines are more like car engines, and are kept inside the boat's hull. In fact, some inboard engines are actually modified car engines.

While inboard engines offer more power, they are much harder to remove or replace, and maintenance is much more time consuming. Outboard engines are easy to maintain, and are generally less expensive than inboard engines. Outboard engines are also better suited to fishing boats, as the propeller can be removed from the water so as to not disturb any fish. This is not the case with an inboard motor, which may frighten fish away. Both kinds of engines are generally suitable for water sports like water skiing.

Inboard and Outboard Performance

While inboard engines can offer a lot of power, this does not mean that they can perform better in all situations. Outboard motors are more versatile, and can be more easily manoeuvered to allow for better turns and better boat performance over shallow areas. This even applies to uneven sea or lake bottoms that might cause disruptions in the water above.

Do Understand the Difference Between Two-Stroke and Four-Stroke Engines

Those interested in buying a boat engine are faced with another choice when choosing engine type: the choice between two-stroke and four-stroke engines. For a long time, boat owners only had the option of using two-stroke engines, but recent advances in engine technology have made four-stroke engines a viable option as well. The differences between a two-stroke and four-stroke engine mainly lie in how the engines deal with intake, exhaust, compression and combustion. These tasks are accomplished by the pistons in each engine, although a two-stroke engine accomplishes everything in a simple in-and-out motion, while a four-stroke engine uses a different stroke for each task.


Buy an inexpensive engine without evaluating all of the costs. Two-stroke engines are known to be less expensive than four-stroke engines, but they wear out much faster, and require more maintenance. Most two-stroke engines also require a special oil for lubricant, which can be expensive and hard to find in many remote boating areas. Two-stroke engines also make a lot of noise, so it is advisable to plan for the cost of fines when one violates a noise pollution law.

Do Be Careful When Choosing Fuel Type

There are two types of fuel that are used by boat engines: gasoline and diesel. Diesel engines are generally more powerful, and are used for larger and heavier boats that a gasoline engine would have trouble moving. For smaller boats, gasoline is in many cases the only option due to the fact that a diesel engine would be overpowered. Diesel engines are more expensive to buy and repair, although they typically last longer than gasoline engines. Diesel is also less expensive per litre than gasoline.

Boat Material

It is helpful to look at the material a boat is made from. Certain fibreglass hulls can react negatively with the ethanol often added to gasoline as a means of reducing air pollution. This reaction can damage, or even render a boat unseaworthy. However, this can be avoided by carefully transporting gasoline, and by using caution when filling up the boat.

Don't Ignore Environmental Factors

Boat engines, like car engines, create a certain amount of atmospheric pollutants. On top of that, boats can be very loud, which can violate noise pollution laws in many areas. Diesel engines, for example, are much louder than gasoline engines, and can bother people on open water, where noise travels to farther distances. At the same time, diesel tends to smell very strongly, and creates very smelly exhaust that may be unpleasant to some, especially if the boat is left idling too long.

It is helpful to look at the newest models of engines before making a decision. For a long time, two-stroke engines were notorious for causing quite a bit of pollution. However, the newest two-stroke engines have severely reduced how much pollution they cause, making them a viable choice for even the most environmentally discerning boaters. Likewise, even though four-stroke engines are larger, heavier, and more expensive, newer models are extremely fuel efficient. Any extra money spent may be recuperated by saving money on fuel.

Buying a Boat Engine on eBay

Boat engines in many varieties are available on eBay. New engines with the latest technology, as well as used, but serviceable engines can be found for various prices there. Once you have determined what kind of boat you have, and what kind of engine would be the best fit for your boating needs, it is easy to find a good match on eBay. The search bar that is accessible on every eBay web page, is the best tool for finding it. All you have to do is enter a search term such as ' boat engine ' into the search bar. This should provide you with a list of items that fit your search terms. Of course, any search term can be modified for a more narrow, or more general search.

Product Descriptions

When an item that looks like a good fit has been found, it is helpful to read the product description. Doing so can help any buyer understand an item's history, and allow time for buyers and sellers to exchange questions and answers about an item. This, in turn can help make a transaction safer, and allow the buyer to make an informed decision.


Buying a boat engine can be a major ordeal if the buyer is not schooled in all of the available options. However, a boat with a reliable engine can be a powerful recreational tool in a number of different locations. When buying a boat engine, there are three major decisions that must be made: what size the engine should be, what kind of engine it should be, and what kind of fuel is to be used. Understanding these factors requires buyers to evaluate a number of different factors along with avoiding some common pitfalls.

Engine size can affect how heavy a boat is, and therefore how manoeuverable it is on the water. Different engine types can perform differently under different conditions, and can have different environmental impacts. Different fuel types can have different prices, but have major differences in terms of power and engine wear. Understanding the Do's and Don'ts of buying a boat engine can make the process much easier and eliminate some of the doubt that buyers may face.

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