outboard motor 4 hp: the perfect balance of power and weight

Choosing a power plant for a boat is always a trade-off between speed, weight and economy. 4hp outboard motor. This is often the gold standard for owners of inflatable boats and small aluminum boats, and it allows them to safely sleeve the vessel for sleeve, if displacement allows, while remaining in the legal field without requiring registration with the GIMS.

Unlike the weaker 2 or 2.5 horsepower models, the four-horsepower unit offers real freedom of maneuver. Not only can you fish in a quiet backwater, but you can also make the transitions between fishing points, saving time and effort, while often keeping the weight of the engine within the limits that allow it to be carried by one person, which is critical for single fishermen.

The market today offers a huge variety of models, and it is easy for a beginner to get confused about the specifications: two-stroke and four-stroke systems, electric or gasoline start, various ignition systems – all these parameters directly affect the comfort of operation. In this article, we will analyze in detail what lies behind the number 4, and help you make the right choice.

Why 4 horsepower: Popularity analysis

The popularity of this category of engines is due not only to marketing, but also to the strict framework of legislation. In Russia, according to the rules for registration of small craft, engines up to 10.88 kW (which corresponds to about 15 hp) and boats up to 20 meters long do not require registration. if their total power does not exceed 10 hp However, there is an important caveat: many models with a capacity of 4-5 hp weigh less than 20 kg in working condition, which allows them to be used with light PVC boats without a complex weighing and design procedure.

Four horsepower is the threshold after which the full planing for most single and one-and-a-half PVC boats begins. If a 2.5 hp engine barely accelerates the boat to 10-12 km / h, then the four-horsepower unit is able to produce 20-25 km / h with one person on board, this radically changes the nature of the use of the boat.

⚠️ Warning: When buying a used engine, be sure to check the year of release and the condition of the lower unit. If the deadville pipe has deep scratches or dents, this may indicate impacts on stones, which can be fraught with cracks in the gearbox body.

Besides, 4hp outboard motor. It's often a "blowable" version of the weaker models. Many manufacturers (like Tohatsu or Mercury) produce a single cylinder-piston-group platform, limiting power programmatically or through a carburetor, which means you get a margin of safety and a life of a more powerful engine, but with less fuel consumption.

Two-stroke vs. four-stroke: the eternal dilemma

In choosing between 2t and 4th The classic choice for the engine is lightness and simplicity versus economy and silence. Two-stroke engines (2t) are traditionally lighter than their four-stroke counterparts. The difference in weight can be anywhere from 3 to 7 kg, which is a significant indicator for a motor of this power. If you often carry a boat and motor alone, every kilogram counts.

Four-stroke engines (4t) are quieter and more stable at low revs. They don't require a benzo-oil mixture, which makes it easier to operate. However, they are more complex, more expensive to maintain and have more overall dimensions. For fishing where silence is needed, 4t is often preferred, but for quick exit to point 2t benefits from less weight.

Four-strokes have a fuel consumption of about 20-30% lower, and 4-ton engines are more environmentally friendly because they don't throw unburned oil into the water, which is becoming an important factor in popular recreation areas or in protected areas where 2-ton engine restrictions may apply.

• 🚤 Weight: 2t engines usually weigh 11-13 kg, while 4t - from 15 kg and above.
• ⛽ Fuel: 2 t require a mixture of gasoline and oil, 4 t work on pure gasoline.
• 🔊 Noise: The 4t work much quieter, which is important for trolling.

It is important to note that modern 2x With E-TEC or similar oil injection technologies, they've basically lost the main drawbacks of the old models, and they're also more economical and cleaner, but they can cost as much as four-strokes.

Specifications and engine design

Constructively 4hp outboard motor. It's a compact unit where all the units are integrated into a single system, and it's based on a single-cylinder internal combustion engine, and the most important element is the cooling system, and this power class uses water cooling almost everywhere, which ensures stable operation even when you're working at full speed for a long time.

The transmission of such engines usually has three positions: front, neutral and reverse. Switching is carried out manually through the rampill., many models of 4 hp. there is no full gearbox in the classical sense, and the switching occurs by moving the clutch.

Parameter	two-stroke motor	four-stroke engine
Weight (average)	11.5 - 13.5 kg	15.0 - 18.0 kg
Fuel consumption (max)	1.2. - 1.5 l/h	0.8. 1.1 l/h
Resource to overhaul	1500 - 2000 motor-hours	2500 - 3,500 motor-hours
Noise level	Highly	Low.

The ignition system on modern models is often electronic (CDI or TCI), which does not require adjustment of the candle gap during operation, which increases reliability and saves the owner from unnecessary manipulation. Electronic control units (CDI) are extremely sensitive to water ingress and temperature changes during the sharp cooling of a hot motor.

Compatibility with PVC boats and aluminum boats

For PVC inflatable boats, a 4 hp engine is ideal for models ranging in length from 2.8 to 3.5 meters. Shorter boats can be unstable in planing, and for longer boats (over 3.8 m), this power may not be enough for comfortable access to mode, especially at full load.

When installed aluminum-boat (Boats, fireworks, etc.) must be considered their weight. Lightweight aluminum boats up to 3 meters long are perfectly combined with such a motor. If the boat is heavier, the four-horsepower engine will run at its limit, consuming a lot of fuel and not giving the expected speed.

Special attention should be paid to the height of the transom. The standard for small motors is 381 mm (short leg). Installation of a motor with a short leg on a boat with a 508 mm transom will lead to the capture of air by the screw and overheating, since the water intakes will be above the water level.

⚠️ Warning: Never install the engine more powerful than the boat's passport says, and overpowering the boat can cause the transom to collapse and the boat to tip over at full speed, which is deadly.

The weight of the engine is also critical for inflatable boats, and the four-strong motor is often the limit that one person can put on a transom without using lifting mechanisms. If you plan to transport the boat often disassembled, the weight of the engine becomes the deciding factor.

Maintenance and extension of the resource

And The 4 hp outboard motor has been in service for many years, and maintenance is required, and the first maintenance is usually done after running (10 hours), during which time the oil in the gearbox (for 4 t) should be replaced or checked, and the candles cleaned.

Regular change of oil in the gearbox is the key to longevity. It is recommended to change it once a season or every 50-100 motor hours. The color of the oil should be coffee; if it becomes whitish (emulsion), then the water has got into the gearbox through the coils. Operating with water in the gearbox will quickly disable the gears.

• 🔧 Candles: Check and clean every 20-30 hours of operation.
• 💧 Cooling: Washing the system with fresh water after use in salt water.
• 🛢️ Oil: Replacement in the gearbox at least once a year.

It's also important to monitor the condition of the screw. Even a small serrated edge of the blade will cause a strong vibration, which is destructive to the dadeville shaft and the osteoils. When hitting an obstacle, be sure to remove the casing and check the shaft for the beat.

How to properly store the engine in winter?

Pour all the fuel out of the tank and the carburetor. Spin the candles and pour into the cylinder 5-10 ml of engine oil, then turn the starter several times. This will create a protective film. Store the motor in an upright position in a dry room.

Overview of popular models and manufacturers

The market is dominated by several key players: Japanese brands such as Tohatsu and YamahaTheir 4-strong models (for example, the Tohatsu MFS4C or the Yamaha F4CMHS) are highly reliable, but also more expensive, and are the choice of those who value the resource and are willing to overpay for the brand.

Chinese manufacturers (Parsun, HDX, Golfstream) offer more affordable alternatives, often using Japanese technology licenses or copying proven designs. Over the past 5 years, the quality of Chinese engines has increased significantly, and for seasonal use (20-30 days a year), they are an excellent budget option.

In fact, many small Mercurys are renamed Tohatsu, which guarantees excellent quality, but they are often more expensive than the original.

💡

When choosing between an expensive Japanese engine and a budget Chinese for rare use (10-15 days a season), it is wiser to choose a Chinese brand with good service in your region.

When buying, pay attention to the availability of service centers. Even the most reliable engine can require repair, and the lack of spare parts can make vacationing a problem. warranty The official service book is required.

Questions and Answers (FAQ)

Do I need to register a 4 hp outboard motor in GIMS?

The engine itself, which is 4 hp (less than 10 hp), is not subject to registration. However, if the boat is longer than 3 meters long or the weight of the equipped vessel with the engine exceeds 200 kg, registration may be required. In most cases, the bundle of light PVC boat + engine 4 hp does not require registration.

Which gasoline is better to pour into the engine 4 hp?

The use of AI-92 is allowed only if it is explicitly stated in the instructions, but can lead to detonation and a decrease in resource.

Can I suffocate the engine 4 hp to 5 or 6 hp?

Technically, many motors (especially the Tohatsu/Mercury) have latent potential and are swelled by replacing a petal valve or gaskets. However, this takes away the warranty, increases fuel consumption, and can lead to overheating if the cooling system is not designed for increased power.

Why does the engine stop at idle speed?

The most common causes are a contaminated carburetor (idle jicler), an incorrectly exposed angle of ignition ahead or air sucking through a gasket, and the problem can also be in poor-quality fuel or water in the tank.