Choosing a reliable outboard motor for a small boat often turns into a trade-off between power, weight and efficiency. Nissan 9.9 outboard motor For many years, it has been holding a leading position among Russian water engines, and this model, being the actual clone of the time-tested Tohatsu M9.8, has established itself as an “unkillable” unit for PVC boats and light “Kazak”.
Why is this 9.9 horsepower figure so popular? The answer lies in law and physics: Motors up to 10 hp don't require registration with the GIM, which saves the owner from bureaucracy, but 9.9 horses are already capable of planing a loaded boat with two passengers. Nissan Marine We managed to make the standard in our class, retaining the simplicity of the two-stroke design and adding modern comfort elements.
In this article, we will discuss in detail the technical nuances, real opportunities force You'll learn why many owners bring the engine to service immediately after buying it to remove restrictions and how to properly run the equipment so that it lasts for decades. Understanding the internal architecture of the engine will help you avoid typical errors in operation.
Technical specifications and design features
The heart of the unit is two-stroke Despite the modest displacement, engineers managed to remove excellent power thanks to the optimised cylinder blowing system, the design involves two cylinders, which ensures smooth operation at idle speeds and sufficient thrust at the bottom, which is critical for trolling or anti-current movement.
The ignition system in modern versions Nissan 9.9 It is implemented via Capacitor Discharge Ignition (CDI), which means there are no contact interrupters that require constant adjustment of the gap. Electronic ignition It provides a stable spark at all speeds and humidity, making it much easier to start the engine after winter storage. The carburetor here is installed alone, but it is equipped with a pump to pump fuel directly into the carburetor body, which facilitates initial start-up.
The cooling system deserves special attention, and water is sucked through the water intake located at the bottom of the daydwoot and forced to pump to the cooling shirt. Thermostat in this model is absent, which for small capacities is rather a plus, since it eliminates the risk of overheating due to valve failure, but requires the use of high-quality oil to prevent bullies.
⚠️ Warning: Never start a motor without a submerged daydwoot in water or a connected plumbing system. Dry work, even for 10-15 seconds, can cause instantaneous overheating and jamming of the piston group.
For a deeper understanding of the differences between the declared and real parameters, we turn to the specifications table:
| Parameter | Meaning | Note |
|---|---|---|
| Workload | 169 cm | 2 cylinders |
| Maximum power | 9.9 hp | At 5,500 rpm |
| Weight (with screw) | 26 kg | No fuel, no fuel. |
| Fuel consumption (max) | ~3.5 l/h | Full throttle. |
| Recommended oil | TC-W3 | Mineral or semi-synthetic |
The secret of popularity: the possibility of modernization to 18 hp
The main reason why Nissan 9.9 outboard motor The one that's used by experienced water engines is the potential that's hidden, and in fact, the 9.9-horsepower version hides the engine from the 18-horsepower model, and the only difference is the software and mechanical constraints that the manufacturer has set for tax exemptions in different countries.
The process of reworking, or "dekulakization," as it is popularly called, involves replacing the throttle and speed limiter. As standard, the petal valve and carburetor prevent the engine from developing full power. By installing an upgrade kit (often sold separately or put in workshops), you can legally or illegally (depending on the laws of your country) increase the power to the full capacity. 18 horsepower.
What does this do? The speed of planing is almost halved. If 9.9 forces barely lift a heavy boat from the water, 18 forces plane confidently even at full load, but it is worth remembering that the engine life can decrease when you constantly run at the limit speed, and fuel consumption will increase proportionally to power.
How difficult is it to technically rework the 9.9 in 18 hp?
Redesign requires replacing the carburetor throttle with a more efficient one, changing the settings of the carburetor needle and, in some cases, replacing the petal valve. It may also require reflashing the CDI unit or installing a speed limiter with a large threshold, which is difficult to do without special equipment to adjust the mixture.
Fuel consumption and efficiency of operation
The question of appetite of the engine is always acute, especially taking into account the current prices for gasoline. Nissan 9.9 The runoff version consumes about 2.5-3 liters of fuel mixture per hour when driving at half-stroke, which is the average for two-strokes. At full load (maximum gas), the flow can reach 3.5-4 liters per hour.
It is important to understand that a two-stroke engine consumes fuel mixed with oil, the proportion is usually 1:50 (2%) for modern oils or 1:25 (4%) for old-style mineral oils. synthetic oil allows not only to reduce the smoke of the exhaust, but also to slightly reduce the formation of carbon, which indirectly affects the stability of the flow.
The actual flow rate is very much dependent on the height of the boat's rise above the water. If the engine is not matched to the height of the daywut or the propeller has too much stride, the boat will not get on plane, and the engine will work in "tough" mode, consuming maximum fuel at minimum speed.
Use a fuel filter between the tank and the engine. It costs a penny, but saves the carburetor from getting water and dirt from the tank, which often causes unstable flow and thrust failures.
Selection of screws: how to find the perfect balance
Staff on Nissan 9.9 outboard motor It's a 9-inch (9x10) propeller, a versatile solution that allows the boat to move for an outboard motor even when it's loaded hard, albeit at a low speed, and it may not be enough to go into a one- or two-passenger planing.
If your goal is maximum speed on a light boat (PVC with a hard bottom), it makes sense to consider screws with a large pitch, for example, 11 or even 12 inches. However, there is a risk: the engine may not spin to working speeds (5000-5500 rpm), will work at “overload” and quickly fail.
- 🚤 9 inch propeller – for heavy boats, trolling and full load.
- ⚡ A 10-11-inch screw is the best choice for planing with 1-2 passengers.
- 🏎️ 12+ inch propeller - only for light boats and sports riding (requires a speed check).
The material of the screw also matters. Aluminum screws are cheap and easy to repair, but when hitting a stone, they bend, transmitting vibration to the daydwun. Stainless steel is stronger and gives a speed gain of 3-5%, but costs significantly more. For a beginner, it is better to start with quality aluminum.
Maintenance and typical faults
Reliability Nissan Marine It doesn't mean there's no problem. Like any other technique, this motor requires regular operation. maintenanceThe most common operation is to replace spark plugs, and it is recommended to use NGK BR7HS candles or their analogues, changing them once a season or if you have problems with starting.
The second critical node is the water pump. The pump's wing should be changed every 2-3 seasons or when there are signs of overheating (decreased jet "control"). Rubber eventually tans and stops pumping water, even if it is visually intact. It is also necessary to lubricate the dayvut bearings annually and check the glands for water to enter the gearbox.
A typical problem is the loss of sealing of the carburetor. If the motor starts poorly after a long downtime, the membranes are likely to dry or the jellyballs clogged. Cleaning the carburetor with ultrasound and replacing the remix usually solve the problem. Don't forget to also check the tightening of the motor mount bolts to the transom - the vibration of the two-stroke can weaken even well-tight connections.
⚠️ Warning: When storing the engine in the off-season, be sure to drain water from the cooling system. Residual water in the shirt when frozen can split the cylinder block, leading to expensive repairs or engine replacement.
☑️ Seasonal engine maintenance
Comparison with competitors: Tohatsu, Yamaha, Mercury
In the outboard motor market, Nissan 9.9 There are direct competitors. Tohatsu M9.8As mentioned, it's technically the same engine, but Nissan often wins in terms of price and availability of parts in a number of regions, and Nissan often comes with a more comfortable handle.
The Yamaha 9.9 (older two-stroke series) is considered more traction-packed but also heavier and noisier. The Yamaha motors have a reputation for being very reliable, but their maintenance and original parts cost more. The Mercury 9.9 is often renamed Tohatsu/Nissan, but with a different casing aesthetic and sometimes a different carburetor setting.
If you choose between the used Yamaha 9.9 and the new Nissan 9.9, many experts are leaning in favor of the new Nissan due to the warranty and lack of “surprises” from the previous owner.
The choice between the Nissan 9.9 and its direct counterparts often comes down to the price in a particular store and the availability of service support in your area, as the technical base of them is identical.
Final recommendations for purchase and operation
Nissan 9.9 outboard motor It's a smart choice for a small boat owner, and it combines years of proven design, affordable price and high potential for modernization, and it's a motor for those who value simplicity and maintainability over sustainability and the quietness of four-strokes.
When buying, pay attention to the equipment: the presence of a fuel tank, hose and screw in the kit. Make sure that the engine is not a “gray” import without an official guarantee, if this is important to you. Proper running (production of 2-3 fuel tanks at different turns) will lay the foundation for long-term service of the piston group.
Don't be afraid of the two-stroke classics. If you keep the ratio of the mixture and use quality gasoline AI-92/95, this engine can take thousands of hours, the main thing is not to overheat it and regularly change the water in the cooling system during prolonged operation on the tether.
Should I Buy a Nissan 9.9 in 2026?
Despite the tightening of environmental regulations, two-stroke engines remain the king of the small segment due to their light weight and the ability to operate in any position (which is important for inflatable boats).
Frequently Asked Questions (FAQ)
Can I fill up Nissan 9.9 with pure gasoline without oil?
Absolutely not! It's a two-stroke engine, the lubrication of the knots is done by adding oil to the fuel, and running on pure gasoline will cause the pistons to jam in a few minutes.
What is the maximum speed of a 320 cm PVC boat?
With one passenger and a standard propeller, the speed will be about 20-22 km / h After dekulakizing to 18 hp. and selecting the screw, you can accelerate to 30-32 km / h.
Do I need to register the engine 9.9 hp in GIMS?
According to the current legislation of the Russian Federation, engines with a capacity of up to 10 hp (inclusive) are not subject to registration if the total weight of the boat with the engine does not exceed 200 kg.
Which oil is better to pour: mineral oil or synthetic oil?
Mineral oil is better for running and old engines (so as not to wash off the scorched junction). For new and forced versions, semi-synthetic or synthetic with a tolerance of TC-W3 is preferable.