The choice of outboard motor always begins with determining its power, and the figure of 8 horsepower is one of the most popular and popular on the market. It is not just a compromise between the weak 5 hp and the more powerful 9.9 hp, but a full-fledged tool It is this power that allows you to confidently plane on light boats PVC or metal frigates with one adult on board, making this class of technology versatile.
Company Yamaha It's been a leader in the small power segment for years, thanks to its legendary reliability and thoughtful design, and motor owners often celebrate their quiet operation and efficiency, but most importantly, it's a resource that, if properly maintained, is counted in thousands of motor-hours. If you're faced with the choice of overpaying for a brand or taking a cheaper one, then you understand the technical nuances. Yamaha 8 It will help you make the right decision.
In this article, we will take a look at all aspects of operation, from design to the finer points of fuel system tuning, why this engine is often called the “people’s” engine and how to run it right so that the technology will last for decades. We will not go into complex engineering formulas, but will look at the practical aspects that each boating faces.
Structural features and weight specifications
One of the key specifications that you pay attention to when buying an outboard motor is its weight. Yamaha 8 This parameter varies depending on the modification, but on average it is about 25-26 kilograms. middle-of-the-road: The motor is still light enough for one person to carry it from the machine to the water without using a trolley, but already has enough mass to run on a transom.
The engine's Carter is made of a strong aluminum alloy that effectively removes heat and protects the internal machinery. Yamaha This is particularly critical when used in salt water, where corrosion can quickly destroy poor-quality machinery.
The cooling system in this motor is water-based, forced, centrifugal pump, and the water is drawn through holes in the lower unit, which requires careful attention to the purity of the reservoir, and the entry of sand or algae into the system can lead to overheating, so temperature It is a prerequisite for operation.
- 🔹 Reliable aluminum housing, resistant to mechanical damage.
- 🔹 Compact node layout that simplifies access for maintenance.
- 🔹 Ergonomic carry handle, convenient for gripping in gloves.
- 🔹 Protecting lower unit from fouling and impacts on underwater obstacles.
Dynamic specifications and speed mode
As for the speed of the motor, the Yamaha 8 It is able to disperse a light PVC boat with a length of 3.2-3.6 meters to 25-30 km / h. This speed is quite enough for a comfortable movement around the water area, access to fish points or just for walks. gelling It is possible only with the correct loading of the boat and the appropriate position of the transom plate.
For flat-bottomed or heavy PVC inflatable floor (HBB) boats, this engine will be an excellent traction power, it does not require sharp movements with the tiller and gradually gains momentum, while if you overload the boat with passengers or cargo, the engine will run in tension, which will negatively affect the resource of the piston group.
To go plane on flat-bottomed boats, it is often necessary to install transom plates or hydrowings on a lower unit to raise the boat's nose.
Maximum power is achieved at rpms of about 5,000-5,500 per minute, but the cruising speed at which the motor is most economical is in the range of 3,500-4000 rpm. fuel It's minimal, and there's little vibration, and it's not recommended to work at full speed for long periods of time, because it causes wear and tear on parts.
⚠️ Warning: The engine is not operated without water or with the water intake hole closed, and the dry passage of the water pump will disable the oede and impeller in seconds.
Fuel consumption and efficiency of operation
The question of fuel consumption is always acute, especially when fishing or hiking for long periods. Yamaha 8 It consumes an average of 2.5 to 3 liters of full gas per hour, and when driving in economical mode, when the boat is half-planing or slow trolling, the consumption can be reduced to 1.5 liters, which makes the engine very profitable to use compared to four-stroke analogues of the same power, which are heavier and more complex.
To prepare the fuel mixture, high-octane gasoline (AI-92 or AI-95) and high-quality two-stroke oil for water technology labeled TC-W3 must be used. The mixing proportion is usually 1:50 (20 ml of oil per 1 liter of gasoline) for new engines after running, but during the primary break-in it is recommended to make the mixture richer - 1:25. instruction to a particular model.
| Mode of work | Turnover (rpm) | Fuel consumption (L/h) | Speed (km/h)* |
|---|---|---|---|
| Idle move | 1000 | 0.6 - 0.8 | 5 - 7 |
| trolling | 2500 | 1.2 - 1.5 | 10 - 12 |
| Cruiser | 4000 | 2.0 - 2.3 | 22 - 25 |
| Full gas. | 5500 | 2.8 - 3.2 | 28 - 32 |
Using poor-quality fuels or oils with an expired life can lead to the formation of soot on the candle and the piston, which in turn causes kalili ignition and loss of power. quality of the fuel It directly affects the durability of the engine.
Can I use car oil?
The use of car oils for two-stroke engines (even with the marking 2T) in outboard motors is not recommended; they do not have the necessary properties of dissolution in water and can lead to the formation of exhaust windows and the formation of soot, as they are designed to work in a closed loop or with another temperature combustion mode.
Ignition and engine start-up system
The engine is started manually, using the exhaust cord. Yamaha The gears are highly reliable, with strong materials and a large safety margin for the return spring, and many models have a decompression mechanism to facilitate the start, which reduces compression in the cylinder at the moment of the jerk.
Electronic ignition (CDI) system, which eliminates the need to adjust the gap in the interrupter, as in old contact systems, this ensures a stable spark at all speeds and in all weather. The spark plug must be selected strictly according to the manufacturer's recommendations, usually these are models. NGK BR7HS Regularly checking and cleaning a candle is the key to easy start.
☑️ Checking of the ignition system
If the engine doesn't start well, it's often not the ignition system that's the problem, but the carburetor overflow, so you have to open the throttle to the maximum and make a few jerks with the starter, blowing the cylinder out of excess fuel, a technique called "purge mode" that helps you start quickly. engine.
Carburetor maintenance and mix adjustment
The carburetor is the heart of a two-stroke motor, and everything depends on its correct setting: idle speed, flow and stability. Yamaha 8 It's usually a float carburetor with one or two jeelers, and over time, especially when using ethanol fuel, idle jellies can get clogged.
The adjustment is done using quality screws and quantity of mixture. The quality screw (usually brass, located deeper) regulates the ratio of air to fuel at low rpm. It must be twisted to the point (without fanaticism), and then twisted to 1-1.5 rpm, as indicated in the manual. idle a screw of quantity.
⚠️ Attention: A poor mixture (lots of air, not enough fuel) is more dangerous than a rich one. It causes the piston to overheat and can cause burnout. If the engine dies when the gas is opened abruptly, the mixture is too poor.
To clean the carburetor, it is recommended to use special aerosol cleaners and compressed air purges. It is not necessary to disassemble the assembly completely, as you can violate factory settings or damage the gaskets. If the engine begins to "sneeze" or stall under load, first check the purity of the fuel filter-sludge.
Maintenance regulations (TO)
And Yamaha 8 pleased you with reliable work, you must strictly follow the maintenance regulations. The first maintenance is carried out after the first 10 liters of fuel mixture or after 2 hours of operation. During this period, the oil in the gearbox changes and the stretch of all bolt joints is checked, since after running the metal “sets”.
Regular maintenance includes lubricating rubbing parts, checking the lower unit for water in the oil and replacing the spark plug. The oil in the gearbox is recommended to be changed every season or every 100 motor hours. It should be of the color of "coffee milk" only in the event of water, which signals that the ossils are malfunctioning.
Timely oil replacement in the gearbox is the cheapest way to prevent costly repairs to the gears and bearings of the lower unit.
When you can preserve it for the winter, you need to drain the water completely from the cooling system, blow out the carburetor and treat the internal cavities of the cylinders with a preservative. conservation It will allow you to start the engine in the spring from the first jerk of the cord.
- 🔹 Oil change in gearbox: 1 time per season or 100 hours.
- 🔹 Replacement of spark plug: 1 time per season or with difficult start-up.
- 🔹 Lubrication of friction points: before each roll-out on the water.
- 🔹 Testing of water: with each oil change.
How often do I need to change the fuel filters?
Coarse cleaning (in the tank) and fine cleaning (in the engine) fuel filters are recommended to be inspected before each season. If the filter is transparent, it should be clean. When using ethanol-containing gasoline, the filters can be clogged with resins faster, so they may need to be replaced more often - every 1-2 seasons of active use.
Why does the Yamaha 8 engine stop at idle?
Most often, the cause is contaminated idle jelly of the carburetor or the sucking of excess air through the intake manifold, and it is also worth checking the adjustment of the idle screw and the condition of the spark plug. If the candle is black and wet, the mixture is too rich, if the white one is poor.
Can I use the Yamaha 8 engine in salt water?
Yes, Yamaha engines are adapted to work in salt water with anti-corrosion coatings and special alloys, but after each roll-out, the engine must be thoroughly washed with fresh water to avoid salt crystallization and corrosion of aluminum parts.