Choosing the right outboard motor for your boat

An outboard motor is ideal for small boats. This is perfect for an inflatable boat, canoes, dinghies or to add extra power to a sailboat . The outboard is an “all-in-one” engine since it integrates the engine, transmission, reverse gear, propeller. As the name suggests, it is entirely on the outside of the boat. Engine and propulsion are installed directly on the transom. You still must choose the outboard that suits your boat. It is necessary to consider the power supply (gasoline, electric, diesel…), its power, the engine assembly. The brand can also influence your choice. Here are the essentials to know before choosing your outboard motor.

The different types of outboard motors

The outboard motor has the advantage of being able to be raised or tilted to protect fragile parts. But there are different types. These boat engines can run on gasoline, diesel or electric, not to mention the “pod drive”.

The different gasoline engines

As a rule, the gasoline engine is more powerful than the electric motor. It is recommended in waters with strong currents, for large boats, for long distances or to go fast. It has the advantage of being able to refuel with a container carried on board.

The semi outboard gasoline engine combines the outboard gear case with the engine of an onboard. The propeller is perfectly aligned with the direction of the boat.

The Pod drive is an inboard engine, most often diesel, with a transmission placed inside the hull. It is perfectly aligned with the keel of the boat which gives more thrust per horsepower. The steering and gas systems are fully electronic. If they are more expensive to buy, they have the advantage of saving space on board.

In the past, the engines were all two-stroke, but to be \”cleaner\” and less noisy, they can now be two- or four-stroke direct injection. In this case, the oil and fuel are separated and there is no oil residue. The four-stroke ones are like car engines with an oil tank.

With direct injection engines, gasoline is injected directly into the cylinders. Emissions are reduced, fuel is saved and starts are immediate. They allow a smooth slow motion, while being more nervous. The fuel system is hermetic which limits the oxidation of the gasoline.

With electronic injection, fuel is injected into the incoming air for each cylinder. It is a nervous and powerful engine. Usually, fuel consumption is limited and cold starting is not a problem.

In short, a gasoline outboard is perfectly suited to larger boats, if you are looking for power, to cover great distances, and to go faster.

Outboard motors are hardly available in diesel for the general public, although some manufacturers, such as Mercury, do.

Electric motors: what do you need to know?

In some areas, it may be prohibited to use a gasoline engine. The electric motor is then the solution. These motors operate on batteries which must be charged by means of an electrical power source. They have many advantages: they are silent (perfectly adapted for a fishing boat), without gas emission and vibrate little. The electric outboard is a perfect solution for boats under three meters. They are light, require little maintenance and mechanical wear is almost non-existent. The torque is good regardless of the speed.

Before investing in an electric motor, you need to know how far you will typically be going and when you will be using your boat. It is the battery capacity that will make all the difference.

The electric outboard is perfect for boats under three meters, if you are environmentally conscious, navigate nature reserves, enjoy fishing, and prioritize low maintenance. This is ideal for covering short distances and if speed is not your priority. It is necessary to have means of recharging the batteries available or to opt for rechargeable batteries. Lithium batteries are the most suitable, recharge quickly and have a good size-to-weight ratio. To increase the autonomy, it is possible to provide a replacement battery, connect it to a solar panel or connect the 12 V power supply on board.

Choosing the right horsepower for an outboard motor

Power ranges from 0.5 to 450 HP and is not limited to the speed it achieves. It gives better handling even at low speed but also better lift-off if you plan to water ski and, generally, better seakeeping. It is recommended to opt for a power as close as possible to the maximum allowed by the boat. An engine that is not powerful enough will over-consume fuel.

We must therefore consider the weight and dimensions of the boat without forgetting the weight of passengers, fuel, on-board equipment…

You choose the power of your outboard motor based on several criteria. These are the weight and length of the boat, the total laden weight (including people on board, equipment) and currents in the navigation area.

It is considered that for boats 2 to 3 meters long, a 5 HP motor is sufficient when there is little current. For those of 4 meters or more or for the smaller models navigating in waters with strong current, it is better to opt for engines of 5 to 20 HP. You should know that a license is mandatory for engines over 6 HP or 4.5 Kw.

If you are using your boat at full load, it is best to choose an engine that is close to maximum power. If you are sailing alone on board or lightly loaded, the power recommended by the yard is reliable.

Choosing the right motor assembly for your boat

Engine power is not everything. Most outboard motors come in different shaft lengths. As a reminder, the shaft is the distance between the underside of the mounting bracket (which rests on the transom) and the anti-cavitation plate.

To choose the right shaft length, you need to measure the transom. For the engine to be installed correctly, the propeller must be under the hull and the metal plate horizontally above the propeller (anti cavitation plate) must be level with the bottom of the hull. If the motor is too short, the propeller will not be submerged enough; if it is too long, it will be too long. This shaft length is therefore essential to optimize the performance of the boat.

Electric or manual start: Small engines can be fitted with a recoil starter with a small built-in tank. They are lighter. With more powerful engines, an electric start with a charger for the starter battery is recommended.

In short, for low top speed boats that sail flat, a low mount and a standard propeller optimize performance. For fast boats (over 30 knots), a high rig is recommended.


The best brands of outboard motors we recommend

Many brands offer outboard motors. Before choosing, remember to check the presence of a maintenance network nearby. The engines must in fact be checked every year to benefit from a guarantee in the event of damage.

The choice of brand will also depend on the length of the available shaft.

If you opt for an electric motor, Torqeedo was the forerunner in the electric motorization of boats. This brand remains a reference just like Minn Kota or Motorguide.

For semi outboards, Ilmor, Mercruiser and Volvo Penta are safe values. If you go for a two-stroke outboard, look to brands like Evinrude, Mercury, Nissan, Tohatsu or Yamaha. For a four-stroke engine, we can also mention the brands Johnson, Honda and Suzuki .

You have to remember that there is no bad brand and that the best is the one that offers the most suitable type of engine for your boat, with service near you.

All engines are guaranteed for at least three years. Mercury and Evinrude offer a five-year warranty.

Want to choose an engine? Check what we offer here.

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