Choosing an outboard motor for a small inflatable boat or a light metal boat is always a compromise between weight, power and reliability. In the low-power class, namely the 5 horsepower segment, the Japanese brand is a luxury luxury luxury luxury vehicle. Tohatsu It has been a top-notch design for years, offering users a benchmark of reliability, and its two-stroke design makes it incredibly popular with fishermen and hunters who value ease of maintenance and maintainability in the field.
Many owners choose this model due to its ability to work on a mixture of gasoline and oil, which simplifies logistics on long trips to water bodies. Motor for a Tohatsu boat 5 Often referred to as the “workhorse” of small rivers, as it is able to confidently navigate a vessel with two passengers and the necessary equipment, in this article we will discuss in detail the technical features, nuances of break-in and typical problems that a user may face during operation.
Technical specifications and design features
At the heart of this unit is a single-cylinder two-stroke water-cooled engine, which is a very high specific gravity scheme, which is critical for PVC boats where every extra kilogram is felt when carrying, with a cylinder capacity of 94 cubic centimeters, which is the standard for this power class, with a maximum crankshaft speed of 5,500 rp per minute, but it is recommended not to use the engine at the limit constantly to extend the life.
The ignition system is implemented via an electronic CDI (Capacitor Discharge Ignition), which eliminates the need to adjust the gaps in the interrupter, as it was in the old contact systems. carburetor The membrane type ensures stable operation of the engine even with strong rolling boats, which often happens when fishing or sharp maneuvers. The weight of the engine as standard is about 19-20 kg, which allows you to control it manually without the use of a special lifting mechanism.
Other versions for different markets
Japan and Europe have stricter environmental regulations, so engines supplied to these markets may differ in carburettor settings and casting systems intended for the North American market.
It is important to note that there is a forced lubrication system for crankshaft and rod bearings through the fuel mixture, the mixing ratio is usually 1:50 for new motors after break-in and 1:25 during initial burn-in. two-stroke oil TC-W3 is a prerequisite for the long life of the piston group.
- 🛠️ Engine type: Two-stroke, single-cylinder, water-cooled.
- ⛽ Tank volume: Built-in tank for 1.2 liters or the ability to connect an external tank for 12 liters.
- 🔄 Launch: A hand-held starter with a snoring mechanism.
- 📏 The length of the lower unit: Standard (S) 381 mm or long (L) 508 mm depending on the modification.
Fuel consumption and speed
One of the main issues that interests a potential buyer is economy: a two-stroke engine with a volume of 94 cubic cm consumes in a combined cycle about 1.5-2.0 liters of fuel mixture per hour. When quietly moving on glides with one person on board, the consumption can decrease to 1.2 liters, while when fully loaded and moving against the current it increases to maximum values.
Speed performance depends on the displacement of the boat and its contours. For a standard inflatable boat with a length of 2.8-3.2 meters with a hard transom and one person on board, the speed on the water will be 20-30 km / h. tohatsu outboard motor 5 on heavier metal boats ("Kazanka" or "sparrows"), the getting on plane is possible only with one pilot and a minimum load.
To save fuel and reduce noise, install an original or high-quality analog muffler on the engine if the equipment of your region suggests its absence or noisy operation.
It should be borne in mind that the real speed indicators may differ from the data-sheet figures due to the state of the propeller, fouling of the lower unit with algae or improper installation of the motor on the transom. The optimal angle of the trim is selected experimentally: if the boat's nose is too upright, glides will not occur even at full speeds.
| Mode of work | Mixture flow rate (L/h) | Speed (km/h) on a boat 3.0 m | Engine rotations |
|---|---|---|---|
| Idle move | 0.4 - 0.6 | 4 - 5 | 1000 - 1500 |
| Cruiser (50%) | 1.0 - 1.2 | 18 - 20 | 3000 - 3500 |
| Full gas (100%) | 1.8 - 2.2 | 23 - 26 | 5000 - 5500 |
Procedure for proper engine break-in
Running is a critical step, which is responsible for 80% of your engine life. Many beginners make the mistake of immediately giving full gas, which leads to bullying of the piston group due to local overheating of the not-yet-gone parts. The process of running it takes about 10 hours of work or producing 5 tanks of fuel mixture.
In the first hours of operation, you need to use an oil-rich mixture. It is recommended to use a ratio of 1:25 (40 ml of oil per 1 liter of gasoline). The first 10 minutes the engine should work at idle speeds. Then, for the next 50 minutes, you should work at low speeds, not exceeding 2000-2500 rpm.
☑️ Engine break-in plan
After every 2-3 hours of running during the break-in period, it is advisable to take breaks for inspection. Check whether oil leaks from the glands, whether water from the control hole (the "urinal") circulates well. If the water stream is weak or intermittent, immediately shut down the engine and check the cooling system, perhaps sand or algae has entered it.
⚠️ Attention: Never run the engine at full power ("full gas"), regardless of the advice of "experienced" friends, this is guaranteed to overheat and jam the piston in the cylinder.
Carburetor adjustment and idling adjustment
Factory setting of the carburetor Tohatsu Usually optimal for standard conditions, but a change in fuel, altitude or engine wear may require adjustment. The carburetor usually has two screws: a mixture quality screw (L) and a mixture quantity screw (H), although in many modern versions of the 5 hp, the H screw is closed with a plug to comply with environmental regulations and does not require intervention.
The idling is adjusted by the throttle stop screw. If the motor stalls when the gas is discharged or the revolutions are floating, it is possible that the idle channel is contaminated or the gap is not correctly set. For accurate setting, it is recommended to use a tachometer, setting idling speeds in the range of 950-1050 rpm.
If the engine is not running smoothly at high speeds ("choking"), this may indicate a poor mixture. However, before you turn the screws, check the condition of the fuel filters and purges, a common cause of problems is water in the fuel or poor-quality gasoline, which during storage has lost its properties.
- 🔧 Screw L (Low): Regulates the mixture at low speeds and transition modes.
- 🚀 Whit H (High): Regulates the mixture at full speed (often sealed).
- 🎚️ Idle screw: It rests on the throttle lever, adjusting the minimum speeds.
Typical malfunctions and methods of their elimination
Despite the high reliability, the equipment can fail. The most common problem is that the engine starts and immediately stops. Most often the reason lies in the fuel supply system: the mesh filter in the tank is clogged, the fuel filter-sludge is contaminated or the valve in the tank lid is blocked (vacuum effect), Checking begins with unscrewing the tank lid: if the engine is running, then the gas exchange in the tank is disturbed.
The second common case is that there's no spark. The CDI system has a switch or a ignition coil that's burned, often because water is under the casing. It's also worth checking the candle, because if it's wet and black, it's a re-enrichment or a high-voltage wire. A dry candle indicates that the fuel is not going into the cylinder.
90% of problems with the start of the Tohatsu 5 hp engine are related to the quality of the fuel mixture and the state of the spark plug, and not to the breakdown of the internal components of the engine.
You can tell if the engine is overheated by the characteristic crackling (knocking) and vapor. If you notice that there is no water coming from the control hole, stop immediately. It can be caused by a broken pump impeller or clogged cooling channels. Operating the engine without cooling for even 1-2 minutes can deform the cylinder head.
⚠️ Attention: When disassembling a carburetor or fuel system, be careful with gaskets. Using a sealant instead of the original gaskets is unacceptable, since it can dissolve in gasoline and clog the jellyplants.
Conservation and storage in the off-season
The right conservation is the key to starting the engine the first time in the spring. The main mistake is to leave the gasoline in the carburetor and the fuel system for the winter. The gasoline oxidizes, forms resins that clog the carburetor's thin channels dead before being stored, and before being stored, release all the gasoline from the float chamber or shut down the faucet and let the engine stall itself.
After the fuel drain, it is recommended to turn the candle and pour 10-20 ml of engine oil into the cylinder. Then you should smoothly turn the crankshaft with a starter several times (the candle should not be twisted yet to squeeze out the surplus), then wrap the candle back, which will create a protective oil film on the cylinder mirror and prevent corrosion.
Keep the motor upright in a dry room, and if you don't have that option and the motor is stored on a boat, be sure to remove it or provide protection from direct precipitation and ultraviolet radiation, which destroys plastic and rubber seals.
- 🧹 Washing: Be sure to rinse the cooling system with fresh water, especially after use in salt water.
- 🛢️ Lubricant: Lubricate all lubrication points (turn hinges, tiller) with a consistent lubricant.
- 🔋 Defense: Cover the motor with a breathable cover to avoid condensation.
Frequently Asked Questions (FAQ)
Which gasoline is best used for Tohatsu 5 hp?
The best choice is fresh AI-92 gasoline. The use of AI-95 is permissible, but does not provide benefits for this engine, and in some cases can lead to a higher temperature operation, the main thing is that the octane number meets the requirements and the fuel is not old.
Can this motor be used in salt water?
Yes, Tohatsu engines are corrosion-resistant, but after each outing, the cooling system must be thoroughly washed with fresh water and exposed metal parts (screw, lower unit) with water-repellent lubricant to prevent rapid corrosion.
Why does the engine smoke when it's working?
Gray smoke is normal for a two-stroke engine, especially when running or at high speeds. If the smoke is black and caustic, it may be that the proportion of the mixture is disturbed (too much oil) or the carburetor (rich mixture) is not configured correctly.
How often do I need to change the fuel filters?
It is recommended to check the condition of the mesh filter in the tank and the sump before each season. If you use canisters for fuel storage, it is advisable to use an additional filter funnel when refueling. The internal fuel filter cup should be changed every 50-100 hours or once a season.