Choosing a power plant for a small vessel often turns into finding the perfect balance between power, weight and price. outboard motor 8 hp 4 stroke It has a special place, offering owners of inflatable and aluminum boats a middle ground, which allows for the confident plane of most PVC boats up to 3.6 meters long with one or two passengers on board.
The current market is saturated with offers, and it is easy for an untrained customer to get confused about the specifications. The four-stroke engine scheme has become the standard of reliability and environmental friendliness, displacing outdated two-strokes from everyday use. Unlike their predecessors, such units do not require mixing gasoline with oil, which greatly simplifies the life of a fisherman or tourist.
Besides, four-stroke It provides more stable operation at low revs, which is critical for trolling or slow movement in waters with sonar. Low noise and lack of caustic exhaust allow you to enjoy nature without scaring fish or annoying the surrounding vacationers. In this article, we will discuss in detail the technical nuances, advantages and features of operation of this category of engines.
Advantages of a four-stroke scheme in the 8 hp class
The main argument in favor of buying a four-stroke unit is its fuel-efficiencyThe design of the engine, where each bar does useful work, allows you to burn fuel more efficiently, which in practice means that a tank of 12-14 liters will last you for a whole day of active fishing or cruising, whereas a two-stroke analog would require refueling by lunch.
The second important factor is environmental friendliness, cleanliness, and not having to add oil to gasoline completely eliminates the risk of misproportion of the mixture, which is harmful to the piston group. AI-92 or AI-95 in the tank, which is especially convenient in the field, when there is no measuring glass and canisters with oil at hand.
⚠️ Warning: Despite having an integrated oil crankcase, before starting the new engine, be sure to check the oil level with a probe. Factory lubrication may be drained or absent during transportation, and working "dry" will instantly disable the engine.
Also worth noting is the low vibration and noise levels. 8 hp outboard motor. It works much quieter, which reduces operator fatigue, and this advantage is especially appreciated by fishermen using sonar, since constant hum can interfere with concentration, and vibration can distort the readings of instruments on the screen.
For long parking (more than a month), it is recommended to treat the fuel with a stabilizer to avoid the formation of resins in the carburetor, since modern environmental standards of the fuel make it less resistant to storage.
Technical specifications and weight parameters
When choosing an engine, weighty specifications often become a decisive factor. outboard motor 8 hp 4 stroke It usually weighs between 25 and 35 kilograms, which is considerably heavier than two-stroke counterparts of similar power, a weight that should be considered if you plan to often carry a boat alone or use a lightweight soft-bottomed inflatable boat.
However, the increase in mass is offset by better weighting and stability on the water. Heavy lower unit helps the boat to keep its course better, especially when moving against the wave. electronic ignitionIt provides a stable spark in any position of the throttle and in any weather.
The cooling system in these engines is usually water-based, forced, and it takes water through the intake holes in the lower unit and circulates through the channels in the cylinder block, and it's an efficient way to remove heat, but it requires careful attention to the cleanliness of the intake holes, especially when swimming in overgrown water bodies or in shallow water.
Below is a comparison table of the specifications of popular models in this class so you can estimate the range of parameters:
| Parameter | Model A (Japan) | Model B (China) | Model C (Europe) |
|---|---|---|---|
| Power, HP. | 8.0 | 8.0 | 8.0 |
| Weight, kg | 26.5 | 31.0 | 29.5 |
| Work volume, cubic.cm | 212 | 212 | 211 |
| Fuel tank, l | 12.0 | 12.5 | 14.0 |
| Launching system | Manual | Manual | Manual/Electric. |
For which boats is the 8 hp engine suitable?
A power of 8 horsepower is borderline for many types of boats, and the ideal candidate for such a motor is considered to be a great candidate for such a power. PVC With this bundle you can comfortably transport 2-3 people or one fisherman with a full set of equipment, developing speeds up to 25-30 km / h.
For aluminum boats (Kanak, Crimea), this engine will be an excellent option for a quiet movement. However, it should be borne in mind that planing with a full load on aluminum can be difficult due to the larger body mass and a lower slip rate compared to PVC. door-wheel They will not just be an accessory, but a necessity.
It is important to remember the power limit specified in the technical documentation for your boat. Exceeding the permissible power can lead to deformation of the transom or even destruction of cylinders on inflatable vessels. If the boat's passport says "up to 5 hp", the installation of the 8 hp engine will require strengthening of the transom or may be prohibited by the manufacturer.
☑️ Checking the compatibility of the motor and boat
Features of operation and maintenance
A four-stroke engine requires regular but simple maintenance, the bulk of the work is to replace the engine oil, the first time the oil is changed after running (usually 10 hours), then every 50-100 hours of operation or once a season, use special oils with the label. NMMA FC-W, intended for water engineering.
Ignition candles also require attention. In gasoline-based environments with ethanol-containing additives, candles can become overgrown with soda more quickly. Periodic visual checks of the color of the soda (it should be brick-colored) will help diagnose problems with the carburetor or ignition system at an early stage.
⚠️ Warning: When you can preserve the engine for the winter, be sure to drain all the gasoline from the carburetor or use a fuel stabilizer. The remaining gasoline evaporates, leaving resinous deposits that can completely clog the carburetor's jellyplants by next season.
The water cooling system needs to be washed with fresh water after each outlet into salt water or muddy bodies of water, and there are special connections to connect the hose to allow water to be driven through the cooling system on the shore, which prolongs the life of the impeller pump and prevents corrosion of the internal channels.
Comparison with two-stroke analogues
The eternal two-versus-four argument in the 8-hp class has its nuances. Two-stroke engines are 30-40% lighter, which is their main bargaining chip. If you're fishing alone and you have to drag a boat across high banks or with drag, every extra kilogram feels very strong.
However, outboard motor 8 hp 4 stroke Two-stroke engines run on a mixture of oil and gasoline, which implies higher temperature loads and less reciprocating life in active operation. Four-strokes that run on pure gasoline and have a full lubrication system, run much longer before the first overhaul.
Hidden savings
Although a four-stroke engine costs more to buy, its residual value is higher in the secondary market, and the liquidity of such engines is due to the demand from boat owners who care about silence and economy, so it is possible to sell a used four-stroke faster and more expensive.
Also worth mentioning is transportation: a four-stroke motor can be transported in the trunk of the car in any position (although it is better still on the side or vertically), without fear of leaking oil into the crankcase, two-stroke requires strictly vertical transport or complete drain of the mixture, which is not always convenient.
Running a new engine: step-by-step instructions
Proper running is the key to a long life of your engine. The process of grinding parts takes about 10 hours. In the first hours of operation, you can not give full load, but working only at idle speeds is also harmful, because the piston rings may not be worn to the walls of the cylinder.
The breaking in mode is usually this: the first 30 minutes are idling and short-term gas openings are no more than 1/3 of the handle stroke. The next 2-3 hours are running at speeds not exceeding 50% of the maximum power. After that, you can gradually increase the load, avoiding long work at full gas in the first 10 hours.
breaking in mode (example plan):0-0.5 hours: Idle speed + short-term acceleration
0.5-3.0 hours: Up to 50% power (full gas no more than 2 minutes)
3.0-10.0 hours: Up to 80% power (full gas no more than 5 minutes)
After 10 hours: Oil change, start of normal operation
During the break-in, carefully monitor the control stream of water, which should go smoothly powerful stream. Overheating during this period is unacceptable. Also after the first 2 hours of work, it is recommended to check the tightening of the diewood mounting bolts and transom bolts, since vibration could weaken the connections.
High-quality break-in increases the engine life by 30-40% and ensures stable fuel consumption in the future, so do not neglect the manufacturer's recommendations on operating modes in the first season.
Frequently Asked Questions (FAQ)
Can I use 95th gasoline instead of 92th?
Yes, modern four-stroke engines are adapted to use AI-95 gasoline. Higher octane can even reduce the risk of detonation under high loads, but you may not notice the difference in dynamics, the main thing is that the fuel is fresh.
Which screw is better to choose for planing?
A full-load plane often requires a smaller-step propeller (e.g., 8 or 9 inches instead of the standard 10-11) to allow the engine to spin to operational speeds and lift the boat to the bar, especially if it is heavy.
Do I need to remove the motor from the boat during storage?
It is advisable to remove the engine, especially if the boat is kept inflated under load, this relieves the tension from the transom board. If it is impossible to remove, use transax wheels or stands so that the weight of the motor does not deform the transom.
Why does the engine stop at high speeds?
Most often, the cause lies in the fuel system: contaminated jet lathe carburetor, clogged fuel filter or broken ventilation tank (check the valve in the tank cover), and the problem may be in the spark plug or cooling system.