Choosing a power unit for a small vessel is always a compromise between power, weight and cost of operation. For owners of small PVC boats or light aluminum hulls, the ideal solution is often the best solution. Yamaha outboard motor 8 2tThis unit has proven itself as a reliable "workhorse" capable of plane a boat with two or three passengers.
The two-stroke design provides excellent traction at low revs, which is critical for trolling or going against the current. Unlike the four-stroke counterparts, the two-stroke is easier to transport and easier to maintain, although it requires a fuel mix, and many anglers and hunters choose this model for its maintainability and the availability of spare parts in any service center.
It is worth noting that the popularity of this model is due not only to the brand, but also to the balanced technical solutions of the company's engineers. The cooling system, transmission and ignition system here are made with Japanese quality, which guarantees a long service life even with intensive use. Next, we will analyze in detail the technical nuances, features of operation and answer frequent questions of owners.
Technical specifications and design features
The heart of the unit is a single-cylinder internal combustion engine with forced air or water cooling (depending on the modification, but more often water). The displacement is 149 cubic centimeters, which at a compression ratio of 1: 6.8 allows you to develop the declared power of 8 horsepower. The most important parameter is weight: the dry weight of the engine is about 31-33 kg, which makes it quite transportable even for one person of average build.
The ignition system here is implemented through CDI (capacitor discharge), which ensures stable spark formation in all modes of operation. The fuel system uses a Mikuni or Keihin carburetor, which requires periodic adjustment, but is highly reliable. Yamaha 8bhp 2t It is equipped with a standard length lower unit, which is suitable for most boats with a transom height of 381 to 430 mm.
Special attention should be paid to the gearshift system. F-N-R (Forward-Neutral-Back) is driven by a tiller and is clear, but like any two-stroke motor, it is important to follow the right switching sequence to avoid wear on gears of the gear gear gear, and the grease of the rubbing vapors is carried out through the fuel mixture, which imposes its own requirements for oil quality.
A critical parameter for this model is the mixing ratio of gasoline to oil, which is 1:50 for modern Yamaha 2M oils and 1:25 for mineral oils of other brands. Violation of this proportion can lead to overheating of the piston group or, conversely, to coking of candles and silencer.
Fuel consumption and efficiency of operation
One of the main advantages of two-stroke engines is their power density and the ability to quickly enter mode. However, the question of efficiency is often acute. Yamaha outboard motor 8 2t It consumes about 2.5-3.5 liters of fuel mixture per hour when driving at full gas. On economical mode (about 3000-4000 revolutions), the consumption is reduced to 1.5-2 liters.
By comparison, four-strokes can be 20 to 30 percent more economical, but the difference is offset by the higher cost of the engine itself and its maintenance. The two-stroke scheme allows a smaller tank to achieve the same running performance, which reduces the total weight on the transom. This is especially true for lightweight inflatable boats, where each kilogram affects speed and handling.
The cost of a watch is not only the price of gasoline, but also the cost of a quality two-stroke oil. The use of cheap economy oils is unacceptable, as they leave a stain on candles and in the exhaust channels.
- 🛶 The maximum speed of the PVC boat with a length of 3.2-3.6 m with this engine is 25-30 km / h.
- ⛽ The volume of the built-in fuel tank is usually 12 liters, which provides a power reserve of about 4-5 hours.
- 🔧 Resource piston group with proper maintenance reaches 1500-2000 hours.
Preparation for the season and the first launch
The right break-in is the key to a long engine life. Yamaha 8bhp. It requires running in the first 10 hours of operation, during which time you can't put a full load on the engine, the first 15 minutes you should run idling, then the next 45 minutes - at turns not exceeding half the maximum power.
Before the first start, you need to check the level of oil in the gearbox and make sure that the oil seals are tight. The fuel mixture should be prepared immediately before getting on the water or use stabilizers if the mixture is stored for more than a month. The gasoline should be fresh, with an octane number not lower than AI-92.
The launch procedure is as follows: open the fuel crane, press the primer several times before filling with fuel, move the romple to the "Start" or "Choke" position, pull the starter. After warming up, the flap can be returned to the working position.
☑️ Checklist before first launch
Regular maintenance and maintenance
Timely maintenance avoids costly repairs. Yamaha 2T outboard motors You should follow the rules of procedure, the basic work includes replacement of spark plug, lubrication of knots and check of the lower unit.
Every 50 hours or once a season, it is recommended to have a defect, and special attention is paid to the state of the candle electrode: black nagar indicates a rich mixture or bad oil, white indicates a poor mixture or overheating, and the normal color of the electrode is brick-brown.
It is important to regularly lubricate the rotating points of the romple and the gas-tiller with special marine lubricants that are resistant to water washing, and check the condition of the lower unit for impacts on stones or driftwood, as deformation can disrupt the cooling system.
⚠️ Warning: Never run the motor out of water without connecting to the water supply system (barrel or plumbing). Dry operation, even for 30-40 seconds, will cause permanent damage to the rubber impeller pump and overheating of the cylinder block.
- 🔩 Replacement of spark plugs: every 50-100 hours (BR7ES model or analogue).
- 🛢️ Lubrication of the gearbox: a complete oil change every 100 hours or once a year.
- 🧹 Cleaning of the carburetor: if necessary, if there are thrust lapses or unstable idling.
Comparison with competitors and modifications
In the outboard motor market, Yamaha 8bhp 2t There are serious competitors like Tohatsu, Mercury and Suzuki, but Yamaha often benefits from a wider service network and the availability of original parts. Modifications can differ in the length of the lower unit (S, L, XL) and the type of launch (manual or electric starter, although an 8 hp electric starter is rare).
The comparison table will help to determine the choice:
| Parameter | Yamaha 8bhp 2t | Tohatsu 9.8bhp 2t | Suzuki 9.9bhp 2t |
|---|---|---|---|
| Weight (kg) | 31.0 | 26.0 | 36.0 |
| Workload (cm3) | 149 | 169 | 169 |
| Traction (kg) | 68 | 75 | 72 |
| Features | Reliability, accessibility | Lightness, compactness | Power, traction. |
It is worth noting that many models of Yamaha 8 hp are structurally unified with more powerful versions of 9.9 hp This allows in some cases to carry out tuning (replacement of the limiter in the carburetor), but such actions remove the engine from the warranty and may not be safe for light boats.
Secrets of tuning Yamaha 8 hp
Many owners know that 8 and 9.9 hp engines often have the same cylinder block. Power restriction is implemented through calibration of the carburetor and petal valves. In theory, replacing the jelly and petals can add 1.5-2 hp, but this requires professional tuning and leads to increased fuel consumption.
Typical malfunctions and methods of their elimination
Even the most reliable unit can fail. The most common problem of two-strokes is the loss of a spark. First of all, you should check the candle and the cap. If there is a spark, but the engine does not start, the problem may be in the fuel system: clogged with the jeekler carburetor or damaged fuel hose.
Overheating of the engine is often accompanied by loss of power and a characteristic whistle, the main reason is the entry of foreign objects (algae, sand) into the pump intake hole, you need to immediately turn off the engine and clean the cooling system.
Shifting problems can occur because of weakening of the cable or wear of the backstage of the mechanism, through the screws on the cable bracket, and it is important not to pull the cable so as not to damage the gear selection mechanism inside the lower unit.
When storing the engine in the off-season, be sure to drain the remnants of the fuel mixture from the carburetor by twisting the drainage screw. The remaining gasoline will evaporate and the oil will coke, leading to launch problems next spring.
⚠️ Attention: If there is a knock in the engine or a sharp vibration, uncharacteristic of normal operation, operation must be stopped immediately. Further work can lead to the twisting of the rod liners and jamming of the crankshaft, which will require major repairs.
Frequently Asked Questions (FAQ)
Can I use it? Yamaha 8bhp 2t On a 3-meter long PVC boat?
Yes, it's the best option. The engine is light enough not to overload the transom, and has enough power to put a boat with one or two passengers on a plane, the main thing is to follow the manufacturer's recommendations for maximum engine power.
Which oil is better to put in the fuel mixture?
It is recommended to use the original oil. Yamaha 2M Or TC-W3 analogues (e.g. Motul, Shell) Mineral oils are cheaper, but require more candle cleaning and more soda, and synthetics provide better lubrication and cleaner engine.
Why does the engine stop at idle speed?
The most likely cause is contamination of the carburetor or air suction through the gaskets, and it is also worth checking the adjustment of the screw quality of the idle mixture, sometimes the problem lies in the wrong angle of ignition or failure of the coil.
Do I need to keep the engine for the winter?
Conservation includes: fuel drain, oil treatment through the candle hole, lubrication of external components and storage in a vertical position in a dry room, which will extend the life of the unit for years.
⚠️ Warning: When transporting the motor by car or trailer, always fix it in an upright position or on a special bracket with a slope prescribed by the instruction. Prolonged storage or transportation "upside down" will lead to oil entering the combustion chamber and hydraulic shock at start-up.
The Yamaha 8 hp 2t outboard motor is a time-tested solution for light boats, combining simplicity of design, high maintainability and affordable cost of ownership.
In summary, it can be said that Yamaha outboard motor 8 2t It remains one of the leaders in its class, and its technical specifications are fully compliant with recreational boating, and with proper care and timely maintenance, this engine will last for many years, providing safe and enjoyable walks on the water.