Choosing a power unit for a small craft always involves finding a trade-off between cost, reliability and weight. Buy a Mikatsu 20 two-stroke outboard motorSo your priority is maximum thrust with minimal structural weight. Two-stroke units with a capacity of 20 horsepower are traditionally considered the "golden mean" for inflatable boats with a length of 3 to 4 meters, providing a confident exit to planing even with full load.
The modern market offers many alternatives, but Chinese brands such as MikatsuThey're very affordable, very resilient, and unlike the expensive Japanese, they save a lot of money on the start without sacrificing basic functionality. It's important to understand that the two-stroke circuit sets different operating rules that are very different from the four-stroke ones.
In this article we will analyze in detail the technical nuances, the real consumption of the fuel mixture and the features of the maintenance model. M20BMSYou'll learn why this power is often the limit for transs of standard PVC boats and how to run the engine properly so that it lasts for years, and how to use it correctly will avoid common mistakes of beginners.
Technical specifications and design features
Model Mikatsu M20BMS This is a classic example of a forced air-cooled engine with a carburetor fuel system, with a cylinder displacement of 344 cubic centimeters, which in a two-stroke cycle provides excellent thrust. It has a single cylinder, which makes maintenance easier, but requires careful attention to the quality of the lubricant.
The key element is the Capacitor Discharge Ignition (CDI) system, which guarantees a stable spark even when operating at low revs. The engine weight in the dry state is about 41 kilograms, making it quite liftable for one person, but requires careful installation on a transom. Steering control implemented through a pump, which has an ergonomic gas control handle and an emergency stop button.
⚠️ Warning: The cooling system works by taking water from the water intake. Never start the engine out of the water or with the fence opening closed, as this will cause instant overheating and deformation of the cylinder head.
To understand the scale of the specifications, let’s compare them with typical representatives of the class in the summary table:
| Parameter | Mikatsu M20BMS | Average 2 tactile 20 hp | four-stroke |
|---|---|---|---|
| Power (hp) | 20 | 18-20 | 20 |
| Weight (kg) | 41 | 40-45 | 55-60 |
| Workload (cm3) | 344 | 330-350 | 360-400 |
| Type of cooling | Watery | Watery | Watery |
Particularly noteworthy is the gear ratio of the gearbox, which in this model is optimized for working with medium pitch screws, which allows you to effectively use traction in glides, minimizing friction power losses in water. The reliability of the materials of the housing is confirmed by the use of aluminum alloys with anticorrosion coating.
Hidden power
Mikatsu motors often have a hidden resource for modernization, but opening carburetor seals automatically removes the product from warranty service.
Advantages of two-stroke scheme for small boats
Decision Buy a Mikatsu 20 two-stroke outboard motor Two-stroke engines lack a complex system of valves and oil crankcases, which makes their design extremely simple and maintainable in the field. The absence of the need to control the level of oil in the crankcase (it burns with gasoline) saves the owner from the risk of turning the liners when the boat rolls.
Transportability is another powerful argument: With the ability to transport in any position (although it is better to avoid an inverted state), a two-stroke can easily be put into the trunk of a passenger car or even into the volumetric cabin of an SUV. Four-stroke analogues require strictly vertical transportation, which creates logistical difficulties.
- 🚀 High power specification: Less weight per horsepower makes it easier to take the boat to the plane.
- 🔧 Simplicity of construction: The minimum number of moving parts reduces the likelihood of failure away from the service.
- 💰 Affordable price: The cost of ownership and initial price is significantly lower than that of four-stroke competitors.
Two-stroke motors also respond more quickly to the gas handle, which is critical when maneuvering in locks, catching fish on the current, or changing course quickly if necessary, and the lack of inertia that characterizes a heavy four-stroke flywheel makes boat control more responsive and predictable.
Fuel consumption and economic efficiency
One of the most common questions that comes up to those who wish to Buy a Mikatsu 20 two-stroke outboard motorThe two-stroke circuit is actually less economical than the four-stroke circuit, because some of the fuel-air mixture is thrown into the exhaust system before it can burn, but modern carburetor technology minimizes this loss.
On average, fuel consumption is about 6-8 liters of gasoline mixture per hour at full load. With moderate operation at cruising speed (about 30-35 km / h), this figure is reduced to 4-5 liters. For comparison, a four-stroke engine of similar power consumes about 20-30% less, but the difference in fuel price pays off only with very intensive operation (more than 100 motor hours per season).
Remember that savings are achieved not only in gasoline, but also in oil. To prepare the mixture, a special two-stroke oil is used, which is added in a ratio of 1:50 (for modern oils) or 1:40 (for mineral oils). Mikatsu class-like TC-W3 This is critical for longevity engines.
The real savings of the two-stroke engine are achieved due to the low price of the unit itself and the absence of expensive maintenance, and not due to the savings of gasoline.
Proper breaking in: pledge of long service
The process of running is not a formality, but a physical and chemical process of working out rubbing parts. Buy a Mikatsu 20 two-stroke outboard motorBe prepared to devote the first 10 hours of operation solely to engine preparation, neglecting this stage can lead to piston group bullies and loss of compression.
The first stage (the first 2 tanks) should be at speeds not exceeding 50% of the maximum. Do not hold the gas handle in one position for too long, change revolutions periodically. This allows you to evenly distribute the load on the bearings and rings. The second stage (the next 4-5 hours) allows for an increase in load to 70-80%, but full gas is still prohibited.
☑️ Mikatsu 20's break-in plan
After the first 10 hours, be sure to replace the gear gear gear (if it is provided for lubrication) and make a defect. Check the tightening of all bolt joints, especially the fastening of the lower unit to the lower unit and the carburetor, as vibration when running them down could weaken them. It is also recommended to replace the spark plugs with new ones, since the old ones may already be covered with specific soak.
⚠️ Warning: Never run dry or pure gasoline without oil, even short-term operation without lubrication in the mixture will lead to irreversible damage to the cylinder group.
Compatibility with PVC boats and the choice of propeller
The power of 20 horsepower is the limit for many inflatable boats. Buy a Mikatsu 20 two-stroke outboard motorMost boats with a length of 3.2-3.6 meters have a power limit of 15-20 hp Exceeding this liment threatens to destroy the transom and loss of buoyancy in an emergency.
For boats up to 150 cm wide and up to 3.8 meters long, this engine is an excellent solution, providing speeds of up to 45-50 km / h with two passengers. However, for narrower or lighter models (less than 3 meters), this power can be excessive, making driving dangerous on the excitement. In such cases, it makes sense to consider buying a motor with a short lower unit if the boat has a low transom.
The choice of propellers is also crucial. Standard propellers that come with a set often have a pitch designed for medium loads. If the boat is heavily loaded (3 people + equipment), it makes sense to install a screw with a smaller pitch (for example, 9-10 inches instead of 11) This will allow the engine to gain speed more easily and go to the plane, reducing the heat load.
When buying the engine, immediately purchase a spare propeller. A blow to an underwater obstacle on the plane can break the blade, and without a spare your rest will be spoiled.
Maintenance and typical faults
Regular maintenance is a guarantee that your boat-engine The main enemy of two-stroke engines is the load on candles and in the exhaust system, and if you use poor-quality oil or the wrong proportion of the mixture, the engine can start to "trouble" or lose power.
Every year, before the season, it is recommended to carry out the following procedures: lubrication of all friction nodes (barrel bearing, rotating point of the bumper), checking the condition of the anodes (zinc plates) on the lower unit, which protect the body from electrochemical corrosion. If the anode is destroyed by more than 50%, it must be replaced.
A typical problem can be difficult to start after winter storage, and often the reason lies in the old fuel left in the carburetor, which has lost its properties and turned into a resinous substance, so before long storage, the motor must be developed or drained.
How to properly preserve the engine for the winter?
To conserve, you need to drain the remaining fuel from the tank and the carburetor. Then start the engine and let it work to a full stop to burn out the remaining gasoline in the system. Then pour about 5-10 ml of pure engine oil through the candle hole and slowly turn the crankshaft several times so that the oil is distributed over the cylinder. Store the engine in a dry room, in an upright position.
Why does the engine stop at high speeds?
Most often, it's a fuel or air supply problem, check the fuel filter, it could get clogged with dirt, and it could be a leaky crankshaft gland that causes the engine to suck in excess air, poor mix, and the third is high-speed jeekler contamination in the carburetor.
Can I use Mikatsu 20 for trolling?
Two-stroke motors can be used for trolling, but with limitations. At minimum speeds, two-strokes often work unstablely and may stall. For effective trolling, it is better to use an electric traction motor or a special trolling mode if it is provided by electronics (in simple carburetor models Mikatsu does not usually have this mode, you need to rework the screw or use an external valve).
Finally, the decision The Mikatsu 20 2x-stroke boat is a rational choice for owners of medium-sized boats, who value simplicity and maintainability. It is a reliable "working" unit that, with proper care and quality fuel, can take hundreds of hours to travel, giving joy from communicating with water.