Choosing a first or additional engine for a boat is always a balance between power, weight and reliability. Yamaha outboard motor 4 hp It is well-deservedly considered one of the benchmarks in the low power class, combining Japanese build quality with sophisticated ergonomics. PVC boatsSmall boats and even for use as a spare engine on yachts.
Unlike the cheap Chinese, the technology is Yamaha Motor Co., Ltd. It offers predictable water behavior and high maintenance, and many aquatic motorists choose this power, because it often doesn't require registration with the GIMS (depending on the total power of all the engines on the boat), which eliminates unnecessary red tape, but for the technology to last for many years, it is important to understand the nuances of its design and maintenance.
In this article, we will analyze the technical features in detail, compare two-stroke and four-stroke modifications, and give practical tips on running. The key advantage of modern models is the exhaust gas purification system Powerhead Exhaust, which reduces noise and vibration. Let’s dive into the world of reliable water technology.
Technical specifications and design features
The heart of any model is the power unit, and in the case of the Yamaha 4 hp, engineers tried to create the most efficient system. single-cylinder With a volume of 83 cc (in four-stroke versions) or similar parameters in two-stroke modifications, the cooling system is forced, water, which guarantees a stable temperature even with prolonged operation at full speed.
Special attention should be paid to the launch system. Most modern models are equipped with a manual starter with a decompressor mechanism, which greatly facilitates the pull of the cord. Transmission It transfers torque to the propeller through a single-speed gearbox. The gear ratio is usually 2.08, which provides an excellent balance between low-speed traction and top speed.
The dry weight of the engine ranges from 11.5 to 13 kg depending on the presence of an electric starter or generator, making it one of the lightest in its class, which is critical for carrying and installing on lightweight inflatable boats.
When choosing a model, pay attention to the presence of a generator (indicated by the letter G in the name) if you plan to use a navigator or sonar without an additional battery.
Below is a comparative table of the main parameters of popular modifications:
| Parameter | two-stroke T4 | four-stroke F4 | four-stroke F4 CMHS |
|---|---|---|---|
| Workload | 49.7 cm | 83 cm3 | 83 cm3 |
| Lubrication system | Mixing | Separate (casecasecase) | Separate (casecasecase) |
| Weight (kg) | 11.5 | 12.5 | 13.0 |
| Fuel tank | 1.1 l (built-in) | 0.9 litres (built-in) | 0.9 litres (built-in) |
Two-Tact or Four-Tact: Which to Choose?
The question of choice two-stroke and four-stroke The engine is in front of every customer. Two-stroke models, like the series. Yamaha T4They're simpler, they're lighter, they're not afraid of being transported in any position, which is convenient for fishermen who carry the motor in the trunk of a car with the boat, but they require a fuel mix and they make more noise.
Four-stroke analogues (series) F4) are quieter, fuel efficient and do not require oil to be mixed with gasoline, where oil is poured separately into the crankcase, like in a car, which makes operation more comfortable and environmentally friendly, and four-stroke motors have a wider range of torque at low rpm, which is important for trolling.
On the other hand, 4-strokes are sensitive to tilts during storage.
The breaking in process: rules and stages
Proper running is the foundation of a long life for you. Yamaha 4bhp. Many beginners ignore this step, which leads to accelerated wear of the piston group. The process of running in approximately 10 hours. During the first two hours, it is not recommended to develop power more than 50% of the maximum. The engine must operate in a gentle mode so that the parts are worn together.
After the first two hours, you can briefly increase the speed, but not more than 5-10 minutes in a row. Full operation at maximum speeds is allowed only after the first 10 liters of fuel mixture (for 2T) or after 10 motor hours of operation (for 4T). During this period, you also need to often check the presence of a stream of water from the control hole to make sure that the pump works.
☑️ Checklist before first break-in
This is normal for two-stroke engines that use mineral oils. For four-strokesmen, after the first 5-10 hours of operation, it is recommended to replace the oil in the crankcase to remove metal shavings formed when grinding parts.
Fuel system and material consumption
The fuel consumption of 4 hp engines is one of the lowest in the class. four-stroke It consumes about 1.0 to 1.2 liters of gasoline per hour at full gas. Half-power (cruising speed) consumption drops to 0.6 to 0.8 liters. Two-stroke modifications consume a little more, about 1.2 to 1.4 liters, plus oil for the mixture.
For the preparation of the mixture in two-stroke engines Yamaha recommended to use high-quality oils with the marking. TC-W3The mixing ratio is usually 1:50 (20 ml of oil per 1 liter of gasoline) for modern engines, however, for the break-in period, the instruction may recommend a richer mixture of 1:25. Always use fresh AI-92 or AI-95 gasoline.
How do you store fuel?
Oil-infused gasoline (a 2T blend) can't be stored for longer than 2-3 weeks. The oil component loses its properties over time, and the mixture becomes aggressive. If you plan to pause in operation, either develop a tank or drain the mixture. Pure gasoline for 4T engines can be stored for up to 3 months with the addition of a stabilizer.
Fuel filtration is also important, and the built-in fuel filter-sludge must be checked regularly for water and dirt.
Maintenance and oil replacement
Regular maintenance is the key to avoiding water problems. Yamaha F4 It is a mandatory procedure to change the oil in the gearbox and crankcase of the engine, the first time the oil is changed after running, then every 50-100 hours or once a season, and use special oils for outboard motors (usually 10W-30 or 10W-40 viscosity).
The spark plug requires inspection every 50 hours. Black colored garment indicates a rich mixture, white - poor. Normal color of the insulator - brick-brown. the gap of the candle should be strictly within 0.9-1.0 mm. It is also necessary to lubricate the gas cable and the joint point of the tiller with a consistent lubricant to avoid jamming.
Water pump requires attention every 1-2 seasons. Rubber impeller tans over time and loses elasticity, which can lead to overheating. If the water stream becomes weaker than usual, this is the first signal that you need to replace the impeller. Don't ignore this symptom, as overheating can lead to bullies in the cylinder.
Timely change of oil in the gearbox (every 50-100 hours) prevents water from entering the mechanism due to wear of the glands and emulsification of the lubricant.
Typical malfunctions and methods of their elimination
Even the most reliable Japanese One of the common problems is the difficulty of starting after winter storage, often because of stale fuel, which has become a resinous substance and has clogged the carburetor's jelly, and the solution is one: completely disassemble and clean the carburetor with ultrasound or solvent.
Another common problem is that there is no spark. Owners should check the candle, the candle cap and the stop button. Sometimes the contacts under the flywheel oxidize. If the engine is intermittent ("troit"), check the compression and condition of the piston rings. four-stroke motors also have valves knocking at high mileages, which requires adjustment of the thermal gaps.
Vibration at high speeds can be caused by damage to the propeller or hitting the fishing line on the shaft. Always carry a spare screw and tool to replace it. A damaged screw not only reduces speed, but also creates a dangerous vibration that destroys lower unit.
Frequently Asked Questions (FAQ)
Do I need to register a Yamaha 4 hp outboard motor in GIMS?
Under current Russian law, boats with an engine of more than 8 kW (approximately 10.88 hp) are subject to registration. Since the Yamaha 4 hp is about 2.94 kW, this engine does not require registration on its own, however, if two such engines are installed on the boat, the total power will exceed the limit and registration will be mandatory.
What is the best oil to use into the Yamaha 4 hp gearbox?
It is recommended to use specialized transmission oils for outboard motors with markings. API GL-5 and viscosity 80W-90 or 90WIt is important that the oil has additives that prevent emulsification (mixing with water).
Why does the engine smoke white smoke?
For two-stroke engines, white or bluish smoke is a normal phenomenon, which is the product of oil combustion. For four-stroke engines, abundant white smoke can indicate the entry of cooling water into the combustion chamber (burned gasket gasket GBC) or the combustion of oil due to wear of oil removable rings.
Can I develop full capacity immediately after purchase?
No, absolutely not. The engine must pass the 10 hours break-in procedure described in the instructions, and running at full speeds of a cold or unrun engine will lead to local overheating and bullying, which is not a warranty case.