Choosing the first outboard motor is always a balance between the desire to have a power reserve and the need to save budget, as well as take into account the weight of the unit. In the segment of low power, often called “sailing” or “cruising”, the Japanese company has remained the undisputed leader for several decades. YamahaTheir two-strong models have become a kind of “gold standard” for owners of small inflatable boats, floating seats and light aluminum boats.
Why? Yamaha 2bhp. It's not just the brand's legendary reliability that's the mainstay of quiet fishing, but it's often the auxiliary motors, so-called "spare" motors for yachts and large boats, where it's important to be able to get to shore in case the main engine breaks. The variety of modifications allows you to choose the unit for specific tasks, whether it's high-speed planing on a light boat or economical movement on a body of water with full load.
In this article, we will discuss the technical details, compare the two-stroke and four-stroke versions, discuss the real fuel consumption and give practical tips on breaking in that will help to extend the life of your "Japanese" for many years, you will learn why some models require mixing oil with gasoline, while others work on pure gasoline, and how this affects operation.
Technical specifications and design features
The 49 cubic centimeter engine, which produces the claimed two horsepower, is a masterpiece of engineering thought in its class. Yamaha 2 hp The weight of the motor varies depending on tact: two-stroke versions are lighter, which is critical for shoulder carrying, while four-stroke versions are heavier, but quieter and more economical.
The ignition system in these engines is usually an electronic CDI (Capacitor Discharge Ignition), which eliminates the need to adjust the gap of candles and ensures a stable spark at any speed. Cooling is carried out with off-board water through the pump, although it is important to avoid working on dry at low strokes and at start.
An important element of the design is lower unitInflatable boats usually use a standard leg, whereas keel boats with high transverses may require a long leg, and it is also worth noting the safety system: many models are equipped with an emergency engine stopper cable that instantly silences the engine when the operator falls overboard.
⚠️ Attention: Never start the engine without dipping the water intake, even for a few seconds, guaranteed to overheat and deform the impeller pump, and can damage the thermostat.
To understand the difference in size and weight, we turn to the comparative table of specifications of popular modifications:
| Model | Type of engine | Weight (kg) | Tank volume (l) | Transmission |
|---|---|---|---|---|
| Yamaha 2CMHS | two-stroke | 9.8 | 0.9 (built-in) | 1 forward/neutral |
| Yamaha 2SMHB | two-stroke | 10.5 | 0.9 (built-in) | 1 forward / 1 backward / neutral |
| Yamaha F2SMHB | four-stroke | 17.0 | 0.9 (built-in) | 1 forward / 1 backward / neutral |
| Yamaha 2JMHS | two-stroke (Old) | 9.5 | 1.1 (built-in) | 1 forward/neutral |
⚠️ Attention: When transporting a four-stroke engine, it can not be placed on either side. The permissible angle of inclination is strictly regulated by the instructions (usually only on the right side or strictly vertically), otherwise oil from the crankcase will get into the combustion chamber and cause a hydraulic shock.
Two-stroke vs. four-stroke: which one to choose?
It's an eternal water-motor dispute, and in the 2 hp class, it's particularly poignant. Yamaha (signed by the letter M in the marking, for example, 2CMHS) are traditional, simple and light. Their main advantage is the ability to transport in any position, which is extremely convenient when transporting a passenger car in the trunk with a boat.
Four-stroke counterparts (denoted by the letter F, for example, F2SMHB) are quieter, do not smoke and consume less fuel. They have oil in the crankcase and change periodically, like in a car. But there are disadvantages: they are much heavier (the difference can be up to 7-8 kg), more expensive to buy and maintain, and are sensitive to roll when working.
It depends on the scenario, and if you're fishing alone, you're often dragging your boat through the woods, or you're shuffling in a confined space. two-stroke If the priority is silence (which is important when fishing with a sonar or just for comfort), environmental friendliness and not having to mess with mixing oil, then four-stroke The motor is the best solution.
It is also worth considering that Yamaha two-stroke engines are equipped with the system. Yamaha Clean Air Induction They're still smelling the exhaust, but they're not really seeing the exhaust of the four-strokes, but they're still emitting unburned fuel.
Fuel consumption and efficiency of operation
The issue of fuel economy for low-power engines is often marginalized by the small volume of the tank, but for avid anglers it is important. Yamaha 2 hp On average, it consumes about 0.6 to 0.8 liters of gasoline per hour when working at full speed. On small strokes, which account for 80% of fishing time, the flow drops to 0.3 to 0.4 liters.
Four-stroke models in the same class are even more impressive, consuming 20-30% less fuel at the same load, achieved by a more advanced combustion process and no loss of fresh fuel mixture through the exhaust window, which is typical for a two-stroke scheme. However, the difference in absolute numbers at low power is small: for a full day of fishing, you save 1-1.5 liters of gasoline.
It is important to remember the oil consumption. For two-stroke engines, you need to purchase a special oil for water cooling with the labeling of the oil. TC-W3The mixing ratio is usually 1:50 (per 1 liter of gasoline 20 ml of oil) for new engines after running, and 1:25 (40 ml per 1 liter) during running. Use of poor quality oil or violation of proportions leads to coking candles and piston group.
Use only fresh AI-92 or AI-95 gasoline. Fuel that has been in the canister for more than 2-3 months loses its octane properties and can cause unstable engine operation or damage to the membranes of the carburetor.
Economy also depends on the condition of the propeller: a damaged or improperly selected propeller makes the engine run in suboptimal mode, increasing consumption. A standard propeller is often suitable for planing a light boat with one person, but a smaller propeller may be required for heavy boats so that the engine can reach working speeds.
Procedure for proper engine break-in
Running is the most important step in the life of any outboard motor, and Yamaha is no exception. It is in the first hours of operation that all moving parts are laundered: piston rings, cylinder, crankshaft. Neglecting the rules of running can reduce the life of the engine by many times.
The process of running a two-stroke Yamaha 2 hp takes about 10 hours. The first 10 minutes (one tank) engine should run at idle speed or very low speed. At this time, there is a primary lapping. It is important not to give the gas abruptly, but not to keep the engine constantly at the same speed.
☑️ Checklist of Yamaha 2 hp running
After the first hour, you can gradually increase the load by operating at variable speeds. It is strictly forbidden to give full gas (100% throttle) for a long time in the first 10 hours. Short-term accelerations to full gas are permissible, but they should not be more than 5% of the total operating time.
For four-stroke engines, the procedure is similar, but even stricter in terms of oil mode. After the first 10 hours of operation, you must change the oil in the crankcase, because it will contain a lot of metal shavings from grinding parts. crucialThis is a concept that many people ignore when buying used motors without knowing their history.
⚠️ Attention: If you notice overheating during the break-in (the engine stops pulling, foreign sounds appear), immediately turn off the engine. Check the control hole for the launching - the jet must be sure. Lack of water is a sign of a pump breakage or a blockage.
Typical malfunctions and methods of their elimination
Despite its high reliability, the Yamaha 2hp engines are not immune to problems, especially when used improperly. The most common problem is difficulty starting. If the engine does not start, first check for the spark and the condition of the candle. The black candle engarment indicates a rich mixture (a lot of oil or air is not enough), white plaque - poor mixture or overheating.
The second common problem is clogging of the carburetor: In modern models with a fuel injection system (if we are talking about more powerful analogues, but also in carburetor 2 hp too), thin channels are easily clogged with resins from old gasoline. Cleaning the carburetor requires accuracy and the use of a special spray-cleaner.
The cooling system is most often caused by the ingress of sand or algae into the water intake, and if the flow of water from the control hole becomes weak, you need to remove the lower part of the daydwoot and clear the channels, and over time, you also need to designate a rubber pump impeller, especially if the motor has been without water for a long time.
List of main symptoms and possible causes:
- 🔥 The engine is dead on the blanks: most likely, contaminated idle chick of the carburetor or sucked air through the gasket.
- 💨 Vibration: Perhaps the screw is damaged, fishing nets are wound on the shaft or a daydwoot bearing is broken.
- 🌊 No water in the control room: clogged cooling channel, worn impeller pump or damaged gasket between the block and the devvut.
- 🔋 No spark: The switch (CDI), ignition coil or emergency stopper cable has failed.
How to properly preserve the engine for the winter?
Pour all the fuel out of the tank and the carburetor. For two-stroke engines, start the engine on the last remaining fuel to stop itself, so the carburetor will remain dry. Plenty of oil inside the cylinder with conservatory oil through the candle hole. Store the motor strictly vertically in the dry room.
Owner reviews and practical experience
By analyzing the water-powered forums and the feedback from real owners, there are a few key points that people appreciate. Yamaha 2 hp For liquidity: these motors are very slow to lose value and are easily sold even in the second-hand state, which is kind of the currency equivalent in the world of low power.
Many people say that the Yamaha 2 hp parts are available in almost any specialty store, and the design is so simple that many owners perform minor repairs themselves, but there are also complaints: plastic elements of the tiller and handles can crack with UV light over time if you do not cover the engine with a cover.
Owners of four-stroke versions often complain about the weight, admitting that dragging 17 kg with full refueling through the mud is a questionable pleasure, but they unanimously praise the silence of the work: on a four-stroke Yamaha 2 hp you can talk without raising your voice, which is impossible on two-stroke analogues.
The Yamaha 2bhp is an investment in reliability, and the high initial cost is offset by excellent resale value and minimal repair costs over many years of operation.
Also, users are advised to purchase additional accessories immediately after purchase: a transport case, a spare candle, a set of tools and a fuel canister. A regular tank of 0.9 liters is enough for about 2-3 hours of active travel, which may not be enough for long-distance forays.
Frequently Asked Questions (FAQ)
What is the best gasoline to pour in Yamaha 2 hp?
The manufacturer recommends the use of unleaded gasoline with an octane number of at least 90 (according to the research method), which corresponds to the Russian AI-92. The use of AI-95 is permissible, but does not give significant advantages in this class of engines.
Can I keep the Yamaha two-stroke engine in a horizontal position?
Yes, Yamaha two-stroke engines are designed to be stored and transported in any position (on any side), as the oil is mixed with gasoline and lubricates the knots while working, rather than being in a crankcase.
What speed does a boat with a Yamaha 2 hp engine develop?
Speed depends on the displacement of the boat and the weight of the cargo. On a light inflatable boat (PVC) with one person (about 80 kg), the 2 hp engine is able to bring the boat to plane at a speed of 10-12 km / h. With two passengers or on a heavy boat, the speed will drop to 5-7 km / h in displacement mode.
Do I need to register a 2 hp outboard motor in GIMS?
According to Russian legislation, small vessels with an engine of more than 8 kW (about 10.88 hp) are subject to registration. A 2 hp (about 1.5 kW) motor is not subject to registration, regardless of the weight of the boat.