Choosing a reliable power unit for an inflatable or light metal floating craft often becomes a difficult dilemma for a boater. Nissan outboard motor 9.8 Deservedly considered one of the benchmarks in the low-power class, combining legendary Japanese reliability and affordable maintenance costs. This unit, which is the actual clone of the time-tested Tohatsu M9.8, is ideal for fishing, cruising and hunting.
Why is this model so compelling to PVC boat owners and boat owners? It's all about the unique balance of weight, power and maintainability. Unlike today's sophisticated electronic four-strokes, this engine remains a simple mechanical device that even a beginner can understand. Nissan Marine The company managed to preserve the best engineering solutions, making the engine popular in the post-Soviet space.
In this article, we will discuss in detail the technical nuances, forcing capabilities and maintenance features, you will learn how to properly run the device, what are the hidden possibilities for increasing power and why this motor is often called “unkillable”.
Technical specifications and design features
At the heart of the unit is a single-cylinder two-stroke engine with a displacement of 169 cubic centimeters, which provides excellent traction at low rpm, which is critical for planing at full load. CDI (electronic) guarantees stable spark formation in all weather conditions, excluding problems with wet candles.
One of the key features is that the engine does not require the fuel mixture to be prepared in a separate container, but the oil is mixed with the gasoline automatically in the right proportion through the carburetor, which greatly simplifies the refueling and reduces the risk of user error. The dry weight is only 25.5 kg, which makes it easy to transport in the trunk of a passenger car.
The cooling system is built according to the classical scheme: forced circulation of off-shore water through the impeller. Nissan 9.8 The engine is equipped with a thermostat that allows the engine to warm up faster and maintain an optimal operating temperature, and the outlet for water (control jet) is conveniently located for visual monitoring of pump operation.
⚠️ Warning: Before each run, be sure to check the control jet of water. The absence of a jet indicates a malfunction of the pump or a foreign object getting on the water intake, which can lead to overheating and jamming of the piston group in a matter of minutes.
The transporting position is provided by turning the lower unit 360 degrees or fixing in a vertical position, which is convenient for storage in a cramped garage. micron with float chamber provides stable idling and smooth response to the gas handle.
Secret of marking
What many people don't know is that the Nissan marking on these engines is a rebranded product, technically a complete copy of the Tohatsu M9.8B2, and all the parts, except the plastic casing and nameplates, are identical and interchangeable.
Tuning capabilities: converting 9.8 to 20 hp
One of the most talked about topics among owners is the possibility of increasing power. crankcase And the crank-shaft mechanism of this engine was originally designed with a margin of safety similar to 15-horsepower and even 18-horsepower models, which is why the procedure of "smothering" or full tuning up to 20 hp is so popular among water engines.
The modernization process usually involves replacing the petal valve, tearing the exhaust windows and reconfiguring the carburetor. However, the easiest way is to remove the speed limiter (if it is software in older versions of CDI) or replace the switch. guarantee The manufacturer is completely burned.
- 🚀 Replacement of the switch: Installation of the ignition unit from the 15-strong version allows you to remove the software speed limit, adding about 2-3 hp.
- 🔧 Mechanical refinement: Squandering exhaust windows and installing a petal valve from the older model require the qualification of a motorist.
- ⚙️ Carburetor setting: After increasing the power, adjustment of the fuel mixture is necessary to prevent overheating.
It is worth noting that a regular propeller with a diameter of 9 inches can become a limiting factor after tuning. To unlock the potential of 18-20 forces, it is recommended to install a propeller with 10 or 11 inches increments, depending on the type of boat and the weight of the crew. Without replacing the propeller, the engine will “twiste” the speed, but not give an increase in speed.
Tuning the Nissan 9.8 to 15-20 hp is technically possible and widely used, but requires a professional approach to adjusting the fuel system to avoid burning the piston.
Fuel consumption and efficiency of operation
Two-stroke engines are traditionally considered more "gluttonous" compared to four-stroke counterparts, however, Nissan 9.8 It's a spectacular performance in terms of efficiency, thanks to a modern cylinder blowing system, and the average fuel consumption at full gas is about 3.5 to 4 liters per hour.
When driving in trolling mode or on an economical run (approximately 3000-3500 rpm), consumption is reduced to 1.5-2 liters per hour. This makes the engine an excellent choice for long fishing expeditions, where every liter of fuel counts. 12 liters tank (standard) provides autonomy for up to 4-5 hours of travel at medium speeds.
An important aspect is the cost of fuel. Since the engine requires the addition of oil, the overall operating costs increase slightly. The mixing ratio is 1:50 for the break-in engine. TC-W3 oil You need to preserve the life of the crankshaft bearings.
| Mode of work | Turnover (rpm) | Speed (km/h)* | Expenditure (L/h) |
|---|---|---|---|
| Idle move | 1000 | 0 | 0.4 |
| trolling | 3000 | 12-15 | 1.6 |
| Cruiser | 4500 | 25-30 | 2.8 |
| Full gas. | 5500 | 35-40 | 3.9 |
* Speed is indicated tentatively for a PVC boat with a length of 3.2-3.6 m with one passenger. The actual figures can vary depending on the load and the condition of the bottom of the boat.
breaking in: rules and stages
Proper running is the foundation of a long life for you. Nissan outboard motor 9.8Neglecting this stage inevitably leads to bullying in the cylinder and loss of compression. The break-in process takes 10 hours and must take place on a pond, not in a barrel, since it is impossible to ensure normal cooling under load in the barrel.
The first 2 hours (1 tank of fuel) you need to operate the engine at speeds not exceeding half of the maximum. It is recommended to alternate modes of operation, not allowing the engine to work for a long time at constant speeds. The fuel mixture during this period should be slightly richer in oil - a ratio of 1:40 instead of the regular 1:50.
- 🕒 First 2 hours: Working at 50% power, avoiding full throttle opening.
- ⛽ 3:00 to 5:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00: You can briefly open the throttle completely for 1-2 minutes, then discharge the gas.
- 🏁 After 10 hours: Full operation in any modes, transition to the standard oil ratio of 1:50.
During the break-in, the piston rings are lapped against the cylinder walls, during which time there may be increased smoke from the exhaust and unstable work on idles, this is normal, the main thing is to monitor the temperature of the body and the presence of a cooling jet.
☑️ Checklist before the first trip
Typical malfunctions and methods of their elimination
Despite its high reliability, Nissan 9.8Like any machine, it's prone to wear and tear, and most often, owners have problems with the ignition system or the carburetor, and understanding the nature of the malfunction allows them to quickly get back into service.
If the engine doesn't start, the first thing to do is to check for sparks and fuel, and often the problem is to fill the candle when you try to start with the air valve closed, in which case you need to twist the candle, dry the cylinder with a scrolling starter and blow the candle.
⚠️ Warning: When diagnosing a ignition system, never hold a high-voltage wire in your hand while scrolling the starter. Although the current here is not fatal, the impact can cause a reflex pull of the arm and injury to metal parts of the boat or propeller.
Problems with overheating are often associated with the entry of sand or algae into the water intake. Regular visual inspection (checking) of the control jet helps to avoid major repairs. It is also worth paying attention to the condition of the osteoils, since their wear leads to water entering the gearbox, which is signaled by the emulsion (mayonnaise) on the probe.
You don't need a complicated tool to replace candles and maintain a carburetor. You just need a set of candle keys and screwdrivers. carburetor The mixture is produced by the quality and quantity screws, however, the factory settings are usually optimal and require correction only after serious intervention or change in altitude.
For long-term storage (more than 1 month), be sure to produce all the gasoline from the carburetor. To do this, start the engine and shut off the fuel supply faucet, allowing it to stall on its own, this will prevent the jellyclera from souring.
Comparison with competitors and final conclusions
In the market of used and new engines Nissan 9.8 The Yamaha 9.9 (which is also often choke-up to 9.8) is much more expensive, although it offers similar reliability. Chinese counterparts lose as casting and lower unit materials.
The main advantage of the model is liquidity, which is very easy to sell even after several seasons of active use, since the demand for a reliable nine always exceeds supply, and its simplicity makes it ideal for regions where there are no specialized service centers.
To sum up, the Nissan 9.8 outboard motor is a rational choice for most tasks, combining enough power to plane a small boat, low weight and ease of maintenance. The only significant disadvantage is the two-stroke cycle, which requires mixing oil with gasoline, which is an inconvenience for some users.
If you're looking for a motor that starts in any weather, forgives the novice's mistakes, and doesn't require expensive repairs in a season, it's a great buy. With proper care, the engine life easily exceeds 1,000 hours.
What is the best gas to fill in Nissan 9.8?
The manufacturer recommends the use of unleaded gasoline with an octane number of at least 92 (according to the research method, RON). In Russia, this corresponds to the AI-92. The use of AI-95 is permissible, but does not give advantages to this engine, and the presence of alcohol in the fuel can be harmful to rubber elements of the carburetor during prolonged storage.
Can this motor be used in salt water?
Yes, the motor is adapted to work in salt water, but requires more care. After each trip by sea, you need to wash the cooling system with fresh water (you can use an adapter on a garden hose) and lubricate all metal surfaces outside with an anti-corrosion spray.
What is the difference between Nissan 9.8 and Tohatsu 9.8?
Technically, it's the same engine assembled in the same factory, with only the color of the plastic casing (Grey in Nissan, often blue or black in Tohatsu), logos and trim (such as the presence or presence of a carry handle in the basic version), parts are completely interchangeable.
Do I need to change the oil in the gearbox?
Yes, the gearbox oil needs to be changed at least once a season or every 100 hours, which allows you to remove the metal shavings that are produced when the gears are working and check for water in the oil, which signals the wear of the osteoils.