Choosing an inflatable outboard motor is always about balancing weight, power and cost. Many beginners mistakenly believe that any low-powered unit will do for a lightweight PVC boat, but reality dictates its terms. Transportability The whole kit is often a deciding factor, especially if you don’t have the ability to keep the boat assembled or carry it in a trailer.
The modern market offers a huge variety of solutions: from quiet to quiet. electric motors It's up to two-stroke gasoline nausea, and each type has its own unique advantages and disadvantages that must be considered before you buy, and the wrong choice can lead not only to money loss, but also to a decrease in water safety.
In this article, we will discuss all aspects of equipping an inflatable boat with an engine, you will learn how to calculate the necessary thrust, why the height of the daydvut is important, and how to conduct the first break-in so that the engine lasts for many years. Technical literacy The owner is the key to a safe and pleasant walk on the reservoir.
Power calculation: two-stroke or four-stroke?
The first question that comes to mind for a PVC boat owner is: what type of engine to choose? Two-stroke engines are traditionally popular among anglers and hunters because of their ease of maintenance. They are not afraid of long downtime and can be transported in any position, which is critical for the safety of the boat. fly-boat.
Four-strokes are heavier, require strictly vertical transportation and are more difficult to maintain. However, they are more economical, quieter and more environmentally friendly. For boats up to 3 meters long, a two-stroke 2-5 hp is often the only option due to weight limitations. If your boat allows (it has a reinforced transom and a length of 3.2 m), then a four-stroke engine will provide much more. comfort swimming.
When choosing power, you should not only focus on the length of the hull, but also on its carrying capacity. An overloaded boat with a powerful engine becomes unmanageable and dangerous. Always leave a margin of weight for passengers, equipment and fuel. loading It provides better handling and handling.
Selection criteria: weight, lower unit and screw
Engine weight is a parameter that directly affects your back and your mood when you go down. Motors up to 5 hp typically weigh in the range of 10-13 kg, which allows you to carry them to one person. More powerful units require either physical training or the presence of a vehicle. wheel-cartIt is not always convenient on the wild shores.
Particular attention should be paid to the length of the lower unit legs. For inflatable boats, the standard lower unit (S - 381 mm) can be short if the boat has a high inflatable cylinder or is installed. squirtIn such cases, the propeller can capture air ("cavitate"), which reduces efficiency and can damage the engine, sometimes requiring the installation of an elongated lower unit or the use of special adapters.
The type of screw also plays a role. Aluminum screws are cheaper, but when hit by a stone or a snag, they bend and require editing or replacement. Stainless steel is stronger but more expensive. For shallow waters and rocky rivers, high pitch screws or special propellers are often chosen. shielding.
When buying an engine, check the package: candles, keys and instructions. Often the basic version may not have a fuel tank or oil for the mixture.
Transnant reinforcement and engine installation
Inflatable boats require a rigid platform for the motor attachment, a trans board, which in basic models can be made of plywood, but to install the engine is more powerful than 3.5 hp, it needs to be strengthened, using metal plates or additional layers of water-resistant plywood impregnated with water. oliphae or varnish.
The motor is mounted in the center of the transom, even a few degrees of distortion will lead to the boat moving aside and increased fuel consumption, and fastening is carried out using rods that must be tightened with sufficient force to prevent vibration, but not damaging. PVC fabric.
It is important to set the depth of the propeller correctly. The anti-cavitation plate should be about 10-15 cm below the bottom of the boat. If the propeller is too deep, water resistance increases; if it is too shallow, the engine will overheat and lose power.
☑️ Check before the first launch
⚠️ Warning: Never start the motor out of the water (in the air) without a special water tank or connection to the water supply. The lack of cooling will instantly lead to overheating and jamming. pump and the piston group.
Comparison of specifications of popular models
To make this easier, consider a comparison table of popular motor models that are often installed on inflatable boats, which will help you navigate the weight-to-power ratio.
| Model | Type | Power (hp) | Weight (kg) | Cylinder volume (cm3) |
|---|---|---|---|---|
| Tohatsu M2B2 | two-stroke | 2 | 9.0 | 23 |
| Yamaha 2CMHS | two-stroke | 2 | 9.5 | 43 |
| HDX T 3.5 | two-stroke | 3.5 | 13.0 | 50 |
| Mercury 4M | four-stroke | 4 | 25.0 | 87 |
| HDX F 2.6 | four-stroke | 2.6 | 17.0 | 58 |
As you can see from the table, two-stroke models are much lighter than their four-stroke counterparts at similar power. Mercury 4MThey provide more stable operation at low revs, which is important for trolling.
Why are Chinese engines cheaper?
Chinese manufacturers often use simpler aluminum alloys and less precise parts processing, which reduces the cost of production, but many are assembled in the same factories as branded Japanese engines, but under different names.
Fuel mixture and engine break-in
For two-stroke engines, the quality of the fuel mixture is a matter of life and death. Only high-octane gasoline (AI-92 or AI-95) and special oil labeled with the fuel mix should be used. TC-W3The mixing ratio is usually 1:25 or 1:50, depending on the manufacturer's recommendations. The savings on oil will lead to bullying in the cylinder.
The process of running a new engine cannot be ignored. In the first 10 hours of operation (or 10 tanks), you must avoid working at full speed. piston-ring And other rubbing parts.
The first run is better done in a barrel of water or on a pond. After starting, let the engine run at idle speeds for 5-10 minutes, checking for a stream of water from the control hole, which is a signal that the cooling system is working properly.
Proper breaking in increases the engine life by 1.5-2 times and ensures that there are no compression problems in the future.
Maintenance and conservation for the winter
Caring for the engine on an inflatable boat requires regularity, and after each trip on salt water, the engine must be washed with fresh water to prevent it from being used. corrosionThe pivot gear and the rummel should also be lubricated.
Before long-term storage (winter), be sure to generate fuel from a carburetor or use a fuel stabilizer. Gasoline left in the system in a few months turns into resins that clog the jellyplants. The spark plug is better to twist out, drop some oil into the cylinder and make a few turns as a starter.
Store the engine in a vertical position in a dry room. If this is not possible, make sure that the lower unit is securely fixed, and the exhaust hole is protected from moisture and insects.
⚠️ Warning: When conserving, do not leave the engine in a position where water can leak into the exhaust system, which will corrosion the muffler and the piston group from the inside.
Frequently Asked Questions (FAQ)
Can the engine be used more powerfully than the boat manufacturer recommends?
Excessive power can lead to the destruction of the transom, loss of controllability on the planing and even tipping the boat. Always adhere to the marking on the transom plate.
Which oil is better for a two-stroke engine: mineral or synthetic?
For modern motors, it is better to use semi-synthetic or synthetic oils, as they form less soda and are better lubricating. Mineral oils are only suitable for older models or if they are replaced very often.
Why does the engine stop at high speeds?
Most often, this indicates a violation of the fuel supply (clogged jeeler, clogged ventilation in the tank cover) or problems with the ignition system (malfunction of the coil or candle), also the cause may be in the air sucking through the crankshaft glands.
Do I need to disassemble the engine for winter storage?
Complete disassembly is not required. It is enough to carry out conservation: to generate fuel, lubricate the cylinders, replace the oil in the gearbox (if it has not changed for a long time), and lubricate the external moving parts.