Choosing an outboard motor for a small boat or boat often becomes a compromise between power, weight and reliability. Honda 20 outboard motor For many years, it has been a leader in this segment, offering a time-tested solution to the aqueous motors, ideal for those who appreciate Japanese engineering culture and require continuous operation in all conditions.
There is a common misconception that all models labeled "20" are identical. two-stroke versions and more modern versions four-stroke The difference between them is huge, from lubrication to noise and environmental performance, and understanding these differences will help you not overpay for the extra functions or buy a unit that is too simple for complex tasks.
In this article, we will take a look at the technical details, service features and real performance indicators, explaining why many anglers and inflatable boat owners choose this particular technique, and the difficulties they face in operating it.
Technical specifications and design features
The basis of the reliability of the Honda BF20 is the proven design of the internal combustion engine. Depending on the year of production and modification, you can come across different versions. The classic two-stroke version is famous for its simplicity and lightness, while the four-stroke BF20D2 offers a variety of options. low-fuel The weight of the engine varies, but on average it is about 40-45 kg, which allows it to be transported in the trunk of a passenger car without special equipment.
The ignition system in these engines is usually electronic (CDI), which ensures stable start-up even after long downtime. An important element is the cooling system, which can be implemented through a water pump or a combined method. Thermostat in four-stroke models helps the engine to quickly reach operating temperature, reducing wear of parts in the cold season.
Secrets of Honda Labeling
The code BF20D2 stands for: BF - series of outboard motors, 20 - horsepower, D - the presence of a lower unit leg of medium length, 2 - the type of start (electric starter + manual), knowledge of this code will help to avoid errors when ordering spare parts.
The engineers paid special attention to the gearshift system. Forward-Neutral-Reverse It works clearly, without backlashes, which is critical when maneuvering in narrowness or when mooring. Carburetor power system, despite its apparent archaicity, is less demanding on fuel quality than injector counterparts, making the engine popular in remote regions.
- 🚤 Power: nominal 20 hp, which allows you to reach speeds of up to 35-40 km / h on a standard boat.
- ⚖️ Weight: the optimal power-to-weight ratio of approximately 2.2 kg per 1 hp
- 🔧 Resource: With proper care, the engine is able to work more than 3000 hours before major repairs.
Two-stroke or four-stroke: which one to choose?
This is a question that every customer has to ask: the two-stroke versions of the Honda 20 that were produced earlier are very power-intensive and simple to build, and they're not afraid of long downtime, they're easy to repair in the field. fuel They are much higher, and the work is accompanied by a characteristic high-frequency sound and smoke.
Four-stroke modifications (BF series) are quieter and more economical, where oil is not burned with gasoline, but is in a separate crankcase, which increases the life of the piston group. However, such engines are sensitive to roll: they can not be stored or transported on the side without special measures, since oil can enter the combustion chamber.
The choice also includes the cost of ownership: a four-stroke consumes 30-40% less gasoline, which, when you walk actively, pays off the difference in price in several seasons, and a two-stroke wins in acceleration dynamics and the ability to quickly replace candles or clean the carburetor directly on the water.
⚠️ Attention: Never use pure gasoline in a two-stroke engine without first mixing with oil in a ratio of 1:50 (or specified in the instructions), this will lead to bullying of the piston in a few minutes of operation.
Preparation for use and breaking in procedure
Proper running is key to the long life of your Honda 20. Many beginners ignore this step, relying on factory assembly, but grinding parts is necessary. The process takes about 10 hours, during which you can not exceed 50% of the maximum power, which allows the piston rings to sit properly in the grooves, and bearings to distribute the lubrication.
The first run is best done on land, using a barrel of water to make sure the cooling system is working. The jet of water from the control hole should be strong and stable. If there is no water, immediately shut down the engine to avoid overheating.
☑️ Checklist before first launch
During the water break-in, try to change the speeds without working long in one mode. Avoid sharp openings of the throttle. After the first 10 hours, be sure to replace the engine oil (in four-stroke versions) and check the state of the spark plug. The color of the soak on the candle will tell you about the quality of the mixture: brick shade is normal, black is a rich mixture, white is poor.
Fuel consumption and economy
One of Honda's main advantages is fuel efficiency. For the four-stroke version of the Honda BF20, the average consumption is about 5-6 liters per hour at full throttle. At cruising speeds, which are usually 70-80% of the maximum, consumption drops to 3-4 liters. This makes the engine an excellent choice for long transitions.
Two-stroke analogs consume significantly more, up to 8-9 liters per hour at full load, because some of the fuel mixture is simply thrown into the exhaust system. However, on small strokes, when trolling or maneuvering, the difference becomes less noticeable.
| Mode of work | Rotating (RPM) | Consumption (four-stroke), L/h | Consumption (two-stroke), L/h |
|---|---|---|---|
| Idle move | 1000 | 0.6 | 0.8 |
| trolling | 3000 | 2.5 | 3.5 |
| Cruiser | 4500 | 4.2 | 6.0 |
| Full gas. | 5500 | 5.8 | 8.5 |
The economy is directly dependent on the condition of the propeller and bottom of the boat. Swallowing with seashells or grass can increase fuel consumption by 15-20%. Regular cleaning of the bottom of the engine and propeller is an easy way to save money.
Use a fuel filter between the tank and the engine, which will trap water and large debris, saving the carburetor from clogging and unstable operation.
Tuning and propeller selection
The standard propeller Honda 20 is chosen as a compromise for the average boat, but replacing the propeller can dramatically change the performance of the course. footsteps It will allow you to go faster on planing, although the maximum speed will fall.
For light inflatable boats, on the contrary, it makes sense to put a propeller with a larger pitch, which will raise the engine speed in the maximum power zone and add a few kilometers per hour to the speed. It is important to monitor the tachometer: the speed should not exceed the maximum permissible speed specified in the instructions.
A popular element of tuning is the installation of a hydrofoil on a lower unit, which is a plastic or aluminum plate that stabilizes the boat on the go, removes yaw and reduces water resistance, and also helps the hydrofoil to go faster for planing and saves up to 10% of fuel.
- 🛠️ Material of the screw: Aluminum is cheaper and easier to manage, stainless steel is more durable and gives an increase in efficiency.
- 🌊 Cavitation plate: adjusting its angle allows you to adjust the boat's differential without moving the cargo.
- ⚙️ Ratio ratio: The Honda 20 is typically 2.08, which is the standard for this power class.
Typical malfunctions and their elimination
Despite the reliability, the machinery can break down. One of the common problems is the difficulty of starting. If the engine does not start, the first thing you do is check for a spark. Unscrew the candle, press it with a thread against the mass of the engine and pull the starter. If there are no sparks, the problem is the ignition coil or switch.
The second common case is that the engine starts and dies, and the fuel is most often to blame, and the water in the tank, the old gasoline, or the carburetor's jammer keeps the mixture from flowing into the cylinder. Washing the carburetor with ultrasound or an aerosol cleaner usually solves the problem.
⚠️ Attention: When removing the carburetor, carefully monitor the integrity of the gaskets. Using a sealant instead of the original gaskets is unacceptable - it can dissolve and clog fuel channels.
The third symptom is overheating. If the control jet is weak or absent, the impeller pump may be worn out or the cooling channels are clogged, and if the engine is operated without cooling, the cylinder head will deform in minutes.
Always start with the simplest: checking fuel, candles and air filters. 80% of problems are solved at this stage without disassembling the engine.
Frequently Asked Questions (FAQ)
What oil to fill in the Honda BF20 (four-stroke)?
Use 10W-30 or 10W-40 viscosity motor oil labeled with API SG, SH, SJ or SL. For marine conditions, oils with NMMA FC-W additive package are preferred, which are better protected against corrosion.
Why does the Honda 20 engine smoke on idle people?
In four-stroke engines, blue smoke indicates oil entering the combustion chamber (wearing off oil rings or valve ossels). In two-stroke engines, idling is normal if the proportion of the mixture is correct.
Can I keep the Honda 20 engine on my side?
Four-stroke models categorically can not be stored on the side or upside down without draining oil, as it will flood the cylinder. Two-stroke engines in this regard are less demanding, but also require caution when transporting.
Which gasoline is best used?
The recommended use of AI-92 or AI-95 gasoline is fresh, and gasoline that has been in the tank for more than 2-3 months loses its properties and can coke the carburetor.