Choosing a hinged engine for a small inflatable boat always involves finding a balance between price, weight and reliability. Sharmax outboard motor 4 hpIt is often seen by newcomers as the first step into the world of water motors, a compact device designed to move lightweight swimmers such as PVC boats or small metal "Kazanki".
Many fishermen and hunters choose this power, as it allows not only to move comfortably around the pond, but also does not require complicated registration in the GIMS in some cases, if the total weight of the kit does not exceed 200 kg.
However, before making a purchase, you need to thoroughly analyze the design features, real opportunities and hidden nuances of the operation of this model to avoid disappointments on the water.
In this article, we will conduct an in-depth analysis of technical specifications, consider the ignition system, carburetion and service features so that you can make an informed decision.
Technical specifications and design features
Engine. Sharmax 4 It is a classic two-stroke forced water-cooled unit, with a cylinder displacement of 72 cubic centimeters, which is the standard for this power class, designed to be as simple as possible and maintainable in the field.
The weight of the engine in running order (without fuel) is about 13.5 kg. This allows you to transport it in the trunk of a passenger car or even in a large backpack, if you use a special carry-on bag. Sharmax 4bhp. It is equipped with a standard length lower unit, which makes it versatile for most trans inflatable boats.
The gearshift system is mechanically implemented through the rotation of the tube, and there are no complex electronic control units, which reduces the likelihood of failure, and the forward, neutral and reverse gear are activated by turning the gas handle, which is common for most water motors.
- 🔹 Engine type: two-stroke, single-cylinder
- 🔹 ignition system: CDI (electronic, contactless)
- 🔹 Start system: manual starter (fuel pump)
- 🔹 Recommended fuel: AI-92 with oil in the ratio of 1:25
⚠️ Warning: Unlike the four-stroke engine, this engine requires a mandatory fuel mix, and the use of pure gasoline will lead to a piston bully and engine failure in a matter of minutes.
It's important to note the quality of the materials. Carter is made of aluminum alloy, which is good at removing heat, but requires careful handling during transportation, because if you hit rocks hard, chips are possible.
Dynamics and speed indicators on the water
The actual performance of the engine depends on the displacement of the boat and the weight of the passenger. On a light PVC boat with a length of 2.7-2.9 meters with one person (total weight of about 150 kg). 4hp outboard motor. It is capable of developing speeds up to 12-14 km / h.
When you increase the load, for example, when you leave two people or use a heavier boat, the speed drops to 6-8 km / h. In this mode, the engine operates in an economical range, consuming minimal amount of fuel, This is the ideal mode for trolling or quietly moving to the fishing point.
If you try to bring into the planing boat heavier than 200 kg, the power of 4 horsepower may not be enough. The engine will work at the limit of its capabilities, emitting a characteristic high sound, but the desired getting on plane will not happen.
Consider that the default screw has a pitch optimized for medium loads. Replacing the propeller with a more "traction" (with a larger pitch) may improve things a little, but it won't solve the problem of power shortages on heavy boats.
Power supply system and fuel mixture preparation
The heart of the power system is a float carburetor, which is easy to set up, but sensitive to fuel quality. Sharmax 4 An AI-92 or AI-95 gasoline is required, and the use of fuel with an octane rating below 92 is unacceptable and can cause detonation.
The key to use is the proper mixing of gasoline and oil. During the break-in stage (the first 10 hours) it is recommended to use a ratio of 1:25 (40 ml of oil per 1 liter of gasoline). After break-in, you can switch to a mixture of 1:50 if you use a quality synthetic oil for two-stroke engines.
Formula 1:25 for the mixture:1 liter of gasoline = 40 ml of oil
5 liters of gasoline = 200 ml of oil
10 liters of gasoline = 400 ml of oil
Remember to shake the canister carefully before each refueling, as oil is heavier than gasoline and can settle to the bottom. Uneven oil flow into the cylinder is a common cause of overheating of the piston group.
- 🛢️ Use only special oils for two-stroke motors (marking 2T)
- 🛢️ Do not store the finished mixture for longer than 2-3 weeks, it loses its properties.
- 🛢️ Before long-term storage (winter) be sure to produce fuel from the carburetor
For accurate dosing of oil buy a special measuring cup with calibration or use a syringe of 20 cubes - it is cheaper and more reliable than measuring "by eye".
Maintenance and routines
Engine resource Sharmax 4bhp. The owner must regularly check the condition of the spark plug, clean the carburetor from contamination and lubricate rubbing nodes.
Special attention should be paid to the water cooling system. After each trip, especially in shallow water or overgrown areas, the control hole should be visually inspected to check the water output. If the jet is weak or absent, the impeller of the pump may be clogged.
| Interval | Operation | Action. |
|---|---|---|
| Every launch | Visual examination | Checking the integrity of the body, the presence of fouling |
| Every 10 motor hours. | Ignition candle | Cleaning up the scoop, checking the gap |
| Every 50 motor hours | Fuel system | Carburetor washing, replacement of fuel filter |
| seasonal | Conservation | Cylinder lubrication, storage in vertical position |
When replacing a spark plug, use only the recommended type, usually NGK B7HS or similar. Installing a "cold" or "hot" candle can disrupt the temperature of the engine.
⚠️ Warning: Never keep the engine horizontally on the side of the exhaust window or carburetor, which can lead to oil leaking into the crankcase and problems starting next time.
Typical malfunctions and methods of their elimination
Like any technique, Sharmax 4 The problem is that you can have typical problems, and most often, users complain about problems starting or unstable idling speeds, and 80 percent of the time, it's because of a poor candle or a misconfigured mix quality screw on the carburetor.
Another common problem is overheating, which occurs when you're running at full speed with a heavily grassed water intake grid, and if the motor starts to lose power and make a whistle, immediately turn it off and clean the cooling system.
☑️ Diagnostics of Startup Problems
Vibration at high revs may indicate an imbalance of the screw or a foreign object (lines, nets) hit the lower unit. Regular inspection of the propeller will help avoid damage to the lower unit pipe.
Comparison with competitors and final conclusions
There are analogues from Tohatsu, Yamaha and Chinese brands like HDX or Sea-Pro on the market. Sharmax outboard motor 4 hp They are often cheaper than famous brands at 20-30% with similar technical specifications.
However, the quality of the assembly and fitting of parts in Sharmax may be inferior to Japanese counterparts, small backlashes of a tiller or lower quality materials of lower unit may occur. For amateur use several times a season, this is not critical, but for commercial use or frequent use, it is better to consider more expensive options.
The hidden resource of the motor
With careful operation and high-quality maintenance, a two-stroke engine with a volume of 72 cc is able to work 1500-2000 motor hours before the first bulkhead of the piston group.
If you are looking for a reliable "worker" for a small boat that does not require complex maintenance and is ready to forgive some errors in operation, then this model will be an excellent choice.
Sharmax 4 hp is the best budget entry ticket to the world of motorboats for single anglers with light PVC boats.
Frequently Asked Questions (FAQ)
Do I need to register the Sharmax 4 hp engine in GIMS?
Under current Russian law, small vessels with an engine of more than 8 kW (about 10.8 hp) are subject to registration. Since the power of this engine is 4 hp (about 2.9 kW), it does not require registration if the total weight of the boat with the engine and equipment does not exceed 200 kg.
Which oil is best used for the mixture?
It is recommended to use semi-synthetic or synthetic oils for two-stroke engines labeled 2T (Two-Stroke). Well-proven oils of the brands Motul, Liqui Moly or specialized oils for outboard motors (for example, Yamalube or Mercury), which have additives against corrosion, which is important for the aquatic environment.
Can this motor be used for trolling?
Yes, the motor is suitable for trolling because it has stable low revs. However, due to the lack of a separate trolling screw, the minimum speed can be a bit high for passive fishing. In such cases, anglers often use transom wheels or additional devices to reduce speed.
What is the real speed on a boat 3 meters long?
On a boat with a length of 3 meters with one person (weight about 80 kg) and a minimum gear, the engine will be able to reach a speed of about 10-12 km / h. With an increase in weight to 150 kg, the speed will decrease to 6-8 km / h, which is the normal mode of operation for this power.