Japanese brand Tohatsu It has long been synonymous with reliability in the boating world. When it comes to choosing a power unit for an inflatable vessel or a lightweight aluminum boat, the 18 horsepower model often becomes the “middle ground” – a class of power that allows the boat to be plane with confidence, overcoming the oncoming wave and current, while remaining easy enough to transport.
Many aqueous motorists choose this range, as it often falls into a category that does not require category B rights to operate a vessel (depending on the total weight of the kit and the legislation). Tohatsu outboard motor 18 hp It is a balance between traction power and efficiency, which is highly appreciated by both anglers and lovers of outdoor activities on the water.
In this article, we will discuss in detail the technical nuances, features of two-stroke and four-stroke modifications, as well as give practical tips for operation. powerplant It will help you avoid common mistakes and extend the life of the equipment.
Technical specifications and model range
The line of engines with a capacity of 18 horsepower at the company Tohatsu It is represented by both two-stroke and four-stroke units. M18A2The PVC is traditionally lighter than its four-stroke counterparts, which is critical for PVC boat owners who often have to carry a transom plate. The weight of a two-stroke is about 36-38 kg, whereas a four-stroke analog can weigh more than 45 kg.
Four-stroke models, for example MFS18A2They have quieter operations and less fuel consumption at cruising speeds. electronic ignition CDI, which provides stable start-up in all weather conditions, and it is important to note that the design of the day-woot engines is optimized to reduce water drag, which has a positive effect on the maximum speed of the vessel.
All models are equipped with forced water cooling, which eliminates overheating even during long-term operation at full speed. Thermostat system allows the engine to quickly go to operating temperature, reducing the wear of parts in warm-up mode. power-generator (usually 6A or 12A depending on the modification) will be a nice bonus for charging the batteries of sonars or navigators.
⚠️ Warning: When choosing between 2T and 4T, consider not only weight, but also the need to mix oil with gasoline. Tohatsu The ratio of 1:50 is used, and a violation of this ratio can cause the piston group to fail.
Below is a comparative table of the main parameters for popular modifications:
| Parameter | Tohatsu M18A2 (2T) | Tohatsu MFS18A2 (4T) | Tohatsu MFS18E2 (4T Long) |
|---|---|---|---|
| Workload | 246 cubic centimetres | 345cc | 345cc |
| Weight (no fuel) | 36.0 kg | 45.0 kg | 46.0 kg |
| Launching system | Manual start | Manual start | Manual start |
| Generator | Optionally (6A) | Got it (12A) | Got it (12A) |
Advantages of two-stroke modifications
Two-stroke engines Tohatsu series M18A2 They are popular because they are simple and lightweight, and structurally they have fewer moving parts, which theoretically reduces the likelihood of failure. For fishermen who often unload the engine ashore or transport the boat in the trunk of a passenger car without a special trailer, every kilogram saved matters.
Modern Japanese-made two-strokes have come a long way in evolution, and they're much more environmentally friendly than their old Soviet counterparts thanks to technology. direct-injection The exhaust smoke is minimized, and the smell of unburned fuel is almost non-existent on cruising modes.
- 🚀 High specific power: fast acceleration and excellent plane access even with a full load of the boat.
- 💧 Transportation in any position: the motor can be placed on its side without completely draining the oil (although it is better to drain the fuel).
- 🔧 Easy maintenance: the absence of a complex oil crankcase and valve simplifies diagnosis in the field.
But you have to keep in mind the fuel consumption, because on low runs, when trolling or manoeuvring in port, a two-stroke engine consumes more mixture than a four-stroke engine, which is due to the nature of the work cycle, where part of the fuel-air mixture is lost during purging.
Features of the four-stroke version of MFS18
Four-stroke Tohatsu MFS18 It's a choice for those who put economy and silence first, and a four-cycle process that delivers a more complete combustion of fuel, which reduces consumption by 30 to 40 percent compared to a two-stroke of similar power, and on long-distance journeys, the savings of gasoline are very tangible for the owner's budget.
The sound of a four-stroke engine running is much quieter and more pleasant to hear, which allows you to talk comfortably in a boat without raising your voice, and less frightening fish when fishing in calm water bodies. Lubrication system In such engines is independent of fuel, so you do not need to prepare a fuel mixture - pure gasoline is poured into the tank.
When running a new four-stroke engine, follow the instructions strictly: do not give full gas for the first 10 hours, and change the oil after the first 20 hours of operation.
Maintenance of the four-stroke requires a more careful attitude to the level and quality of the engine oil; oil changes should be made regularly, usually once a season or every 100 motor hours; and the condition of the air filter, which in four-stroke models plays a critical role in mixing, must be monitored.
⚠️ Warning: Do not allow the four-stroke engine to work Tohatsu Unlike two-stroke models, there is no lubrication with oil added to the gasoline, and bullying in the engine can occur in minutes.
Fuel consumption and economy
Fuel consumption is a key issue in the choice of outboard motor. Tohatsu 18bhp The average full-gas flow rate is about 5-6 liters per hour, and half-throttle (cruising speed) is reduced to 3-4 liters, which is acceptable for a motor of this class, allowing you to travel long distances on one tank.
The four-stroke version is more efficient, with a full-speed flow rate of about 4-4.5 liters, and an economical run of 1.5-2 liters per hour, making four-strokes ideal for long-duration expeditions where refueling is limited.
The flow rate is also affected by the condition of the propeller and bottom of the boat, and by shells or grass, damage to the propeller blades can increase fuel consumption by up to 20%. submersible Motors and boats are an easy way to keep the manufacturer’s stated specifications.
- ⛽ Use gasoline with the octane number recommended in the instructions (usually AI-92 or AI-95).
- 🌊 Consider the effects of wind and waves: moving against the wind increases engine load and fuel consumption.
- ⚖️ Proper loading of the boat: differentiation of the vessel affects the resistance of the water and, as a result, the appetite of the engine.
The four-stroke engine pays off its higher initial cost for 2-3 seasons of active operation due to fuel economy.
Installation and first launch
Mounting the engine on the boat's transom requires several important rules: the height of the installation must be such that the anti-cavitation stove is on the same level with the bottom of the boat or 1-2 cm lower. Too high a landing will lead to air capture and overheating, and too low will lead to increased water resistance.
Before the first start, check the oil level in the gearbox and (for 4T) in the engine crankcase. Make sure the fuel line is sealed and the pear of manual fuel pumping is solid after a few taps. This is a sign that the system is filled with gasoline and ready to go.
☑️ First engine start
The start is done according to the algorithm: move the gas handle to the start position (or squeeze the handle of the pump to the end), pull the starter handle. After warming up for 2-3 minutes, you can start moving. Always check for a control stream of water from the cooling hole before starting to move.
Regular maintenance and care
Durability Tohatsu 18bhp The main enemy of the outboard motor is corrosion, so after each sortie on the salt water, the engine must be washed with fresh water, and for this there are special connections for washing or tank-boots.
Check the spark plug regularly. The candlelight can tell you how the engine works: white plaque indicates poor mix or overheating, black and oily - a rich mixture or piston wear. fuel-filterThe sludge should also become a habit before each season.
How to store the engine in winter?
Pour all the fuel from the carburetor and tank, replace the oil in the gearbox, lubricate the slats, install the motor vertically and cover from dust.
Once a year, it is recommended to conduct a full diagnosis at an authorized service center. Specialists will check the compression, condition of the ods and the water pump. Timely replacement of the impeller pump (every 2-3 seasons) will protect from sudden overheating at the most inopportune time.
Frequently Asked Questions (FAQ)
Which screw is better to choose for Tohatsu 18 hp for an inflatable boat 3.6 meters long?
For a PVC boat with a length of 3.6 meters with two passengers, the optimal would be a regular propeller with a pitch of 10-11 inches. If the boat is heavy or you plan to walk with a full load, you can consider a propeller with a reduced pitch (9-10 inches) to make the engine easier to get to the turns.
Can I fill Tohatsu with 18 hp AI-95 gasoline?
Yes, modern Tohatsu engines are adapted to work with AI-92 and AI-95 gasoline, and higher octane fuel (AI-95) is even preferred to prevent detonation, especially in hot weather or high loads.
Why does the engine stop at idle speed?
The most common causes: pollution of the carburetor (jelly), improper idling adjustment, air sucking through the gaskets or a malfunction of the ignition system (candle, coil), also the problem may be in poor-quality fuel or water in the tank.
Do I need to run a new Tohatsu engine?
Yes, the break-in is mandatory for all new engines. It takes about 10 hours. At this time, you can not give full gas (usually not more than 50-70% of the maximum rpm is recommended) to the parts of the piston group and gearbox were rubbed together.