Choosing a power plant for a small vessel is always about balancing power, weight and reliability. Honda BF20 It has long been a benchmark for Japanese engineering, ideal for light boats, PVC inflatable boats and aluminum kazaks, which require a confident planing under full load experience.
Unlike many Chinese counterparts, the original Honda BF20 It offers not just the stated horsepower, but also high torque at low speeds. It's critical for fishing or trolling, when you need to slowly and steadily pull gear against the current. The design, which has been used for decades, provides a minimum level of vibration, which makes it comfortable to be on the water even throughout the day.
In this article, we will discuss in detail the technical nuances, features of operation and hidden advantages of this particular model, you will learn why many water engines are willing to overpay for the brand and how to properly maintain the unit so that it will last for decades.
Technical specifications and design features
The heart of the model is a four-stroke internal combustion engine with a volume of 350 cubic centimeters, which allows you to achieve high fuel efficiency while reducing harmful emissions. Honda BF20 system applied OHC (OverHead Camshaft)It provides excellent ventilation of cylinders and stable operation at high revs.
One of the key features is the presence of two cylinders, which is the standard of reliability for this power class. The lubrication system works under pressure, not splashing, which significantly increases the resource of rubbing parts. Forced water cooling ensures that the engine does not overheat even during prolonged operation at full gas.
⚠️ Warning: Despite having an emergency stop system when overheating, never operate the motor without a visible jet of water from the control hole. This can cause the piston group to jam instantly.
The engine weight as standard is about 43-45 kg (excluding oil and tank), which is acceptable for manual mounting on a transom. However, for frequent installation and removal, it is recommended to use transom wheels or a winch to avoid back injuries.
The secret of Honda’s durability
The design is based on a cast-iron cylinder block, which is rare in modern lightweight engines, which allows for major engine repairs by wasting cylinders to repair size, instead of replacing the entire unit.
Ignition system and electronic control
For the ignition of the fuel mixture in Honda BF20 It's a CDI (Capacitor Discharge Ignition) electronic ignition system that has no mechanical contacts that can oxidize or wear out, making it virtually unmaintenable, and it's produced at exactly the right moment, ensuring a stable start-up even in wet weather.
An important safety feature is the engine emergency stop system, and the tiller or remote control (depending on the modification) has a stop button that closes to the mass when pulling checks, which is critical in situations where the operator falls overboard.
- 🔥 High-voltage wires have double insulation, protecting against breakdown in salt water.
- 🔋 The generator system allows the battery to be charged while driving, powering navigation devices.
- ⚙️ The ignition advance angle is selected automatically for maximum combustion efficiency.
It is worth noting that some modifications may have an oil pressure indicator that signals problems in the lubrication system, and ignoring this signal can lead to catastrophic failure of the engine.
The electronic CDI system does not require adjustment of gaps and candle replacement is much less common than in carburetor engines of the old type.
Fuel system and economy of consumption
The four-stroke cycle of the engine involves a separate supply of oil and gasoline, which eliminates the need to prepare the fuel mixture. Honda BF20 It is highly stable and rarely requires intervention.
Fuel consumption is one of the main advantages of this model: when driving in economic mode (about 3000-3500 rpm), consumption is approximately 4-5 liters per hour. At full gas, this figure can reach 7-8 liters, which is an excellent result for a 20-horsepower class.
To store fuel, it is recommended to use tanks with a ventilation system and a settling tank for water. The condensation in the carburetor can cause unstable operation at idle speeds or a complete stop of the engine.
The tank has a crude fuel filter that traps large debris, but for full protection, it is recommended to install an additional fine filter separator between the tank and the engine, especially if you doubt the quality of the fuel at the fuel station.
Transmission and propeller
The torque is transmitted to the propeller shaft through a geared gear that operates in an oil bath. The gear ratio of the gearbox is selected to ensure optimal traction under various loads. Honda BF20 The F-N-R (Forward-Neutral-Back) gearshift system is used, which is distinguished by the clarity of moves.
The corkscrew mechanism (dadewood) is protected from impacts on underwater obstacles by a cut pin or friction clutch (depending on the year of release and modification), which avoids breaking the gears of the gear gear when hitting a stone or driftwood.
| Parameter | Meaning | Unit of measurement |
|---|---|---|
| Power | 20 | hp |
| Cylinder volume | 350 | cm3 |
| Max. Turnover. | 5500-6000 | min |
| Launching system | Manual/Electro | - |
| Recommended screw | 9.25 x 9 | lens |
Selection of propellers is a separate science. Standard propellers provide good traction, but plane with full load may require a screw with a smaller pitch. Conversely, for light boats with one operator, the pitch can be increased to achieve a higher maximum speed.
Maintenance and routines
Durability Honda BF20 The first maintenance is usually done after 20 hours or one month of operation, during which time the engine oil needs to be replaced, as the parts are laundered.
Regular maintenance includes checking the oil level, the condition of the spark plugs and lubricating the points of rotation. The oil in the gearbox is recommended to be changed once a season or every 100 motor hours. The color of the oil should be transparent or light brown; the presence of an emulsion (mayonnaise) indicates water entering through the glands.
☑️ Seasonal engine maintenance
Special attention should be paid to the cooling system, periodically you need to remove the pump cover and check the condition of the impeller, rubber petals eventually tan and lose their effectiveness, which leads to overheating.
For preservation for the winter, be sure to drain all water from the cooling system or use antifreeze if the design allows pumping. It is also recommended to treat the external surfaces with special compositions that prevent corrosion.
Comparison with competitors and final conclusions
In the market of 20-horsepower engines Honda BF20 It competes with the Yamaha, Tohatsu and Suzuki models, and Honda's main advantage is its legendary reliability and low noise levels. Japanese engineers have put a special emphasis on balancing the engine, making it very soft.
Yamaha, for example, can offer a slightly higher top speed through exhaust optimization, but often loses traction at the bottom. Tohatsu wins in weight, but can be inferior in resource in intensive commercial operation.
When buying a used Honda engine, be sure to ask the seller to start it “dry” (without water) for only a couple of seconds to check the compression, but never hold it for longer than 10-15 seconds to avoid overheating the pump.
Choosing. Honda BF20This motor will not require constant attention and will work year after year, if you follow simple rules of operation, it is ideal for those who value quality over short-term savings.
In conclusion, it's one of the best in its class, and its combination of power, economy and maintainability has made it a sales hit for years, and if you want a reliable hard worker for fishing or going for a walk with your family, that's a great choice.
Which octane gasoline is best in the Honda BF20?
The manufacturer recommends using gasoline with an octane rating of at least 92 (according to the research method). The use of AI-95 fuel is allowed and even preferably for long journeys, since it provides a more stable combustion and less polluting the combustion chamber with carbon monoxide.
How often should you change the oil in the gearbox?
The first oil change in the gearbox is made after the first 20 hours of running, then the procedure is repeated every 100 hours or once a year, regardless of the mileage, this is necessary to remove metal shavings and moisture.
Can you use the Honda BF20 in salt water?
Yes, the motor is adapted for use in salt water, but after each outing, you need to flush the cooling system with fresh water to prevent corrosion of the internal channels and impeller pumps, and regularly check the condition of magnesium anodes.