Choosing a power unit for a lightweight inflatable boat or a small boat often comes down to finding a balance between power, weight and economy. Yamaha outboard motor 4 hp 4 stroke It has been a leader for many years, and owners appreciate it for its quiet operation, the lack of need to mix gasoline with oil, and the incredibly low fuel consumption that makes it ideal for long-term fishing.
The four-stroke technology that Japanese engineers introduced into this power class has dramatically changed the way small-scale vehicles operate, so users don't have to put up with the smoke of two-stroke analogues and the characteristic smell of unburned gasoline. The engine runs on pure gasoline, which greatly simplifies preparation for the water launch and reduces operating costs per motor hour.
However, despite the popularity of the model, beginners have many questions about the resource, the ability to transport in any position and the features of the first launch. In this article, we will discuss in detail the technical nuances, compare the specifications with competitors and give practical tips for care to your child. Yamaha F4 It has been in service for many years without serious damage.
Design features and technical specifications
The heart of this model is a single-cylinder, overhead camshaft (OHC) internal combustion engine, which delivers excellent low-speed traction, which is critical for full-load plane. The cylinder capacity is 112 cubic centimeters, which is the optimal for the declared 4 horsepower.
The cooling system is based on the principle of forced water circulation through a water pump, which allows you to efficiently remove heat even when working at full speed in hot weather, and it is important to note the presence of a thermostat that maintains the optimal temperature regime of the engine, preventing both overheating and excessive cooling.
Transmission is made according to the scheme Forward-Neutral-ReverseThis distinguishes the four-stroke models from many of the two-stroke models in this class, where the reverse is often absent or implemented through the turn of the lower unit, the gearshift mechanism is soft and clearly fixed positions.
For clarity, we will give the main technical parameters that should be considered when choosing:
| Parameter | Meaning |
|---|---|
| Type of engine | four-stroke, OHC |
| Workload | 112 cm |
| Maximum power | 4 hp (2.9 kW) |
| Launching system | Manual starter |
| Weight (with screw) | 25.0 kg |
The Secret to Low Vibration
The design is based on a balancing shaft, which extinguishes inertial forces, making the engine smooth even at idle.
Economical and environmental friendliness of operation
The main trump card of the four-stroke architecture is the phenomenal fuel economy. Fuel consumption The Yamaha 4-hp four-stroke full-gas outboard motor is only about 1.1-1.3 liters per hour. For comparison, a two-stroke fellow of the same power would consume almost twice as much if mixing with oil were taken into account.
The environmental aspect is also not to be ignored, because the crankcase contains pure engine oil and the gas tank only fills with fuel, the exhaust gases contain significantly less harmful impurities, which is especially important for anglers who spend a lot of time in the confined spaces of the boat and do not want to breathe the combustion products of the mixture.
The lack of fuel mixing removes the owner's responsibility for the right proportions, you no longer have to carry oil canisters and measuring tanks, just have a supply of pure AI-92 or AI-95 gasoline, which makes it easier to logistics travel to remote water bodies.
Use gasoline with the octane number recommended by the manufacturer (usually at least 92) and be sure to add a fuel stabilizer if the engine will be stored for more than a month without work.
Low noise is another nice bonus: the four-stroke combustion cycle and the presence of a separate lubrication system make the unit work quiet and smooth, which allows you to hear the splash of fish or the conversation of satellites without raising your voice due to the roar of the engine.
Advantages for inflatable boats and PVC
Many PVC boat owners are hesitant to take a four-stroke because of its weight. Indeed, 25 kilograms is significantly more than 13-14 kilograms for two-stroke boats. However, when you look at the use cases, the benefits become obvious. The motor is easily carried by one person thanks to its ergonomic handle and compact dimensions.
For inflatable structures, vibration resistance is critical. Yamaha F4 It creates minimal vibrational load on the transom and cylinders of the boat, which reduces the fatigue of the driver and passengers, and also reduces the risk of damage to the adhesive seams or fittings of the boat from constant shaking.
- 🚤 Stable idle It allows you to drift slowly against the current or wind, which is ideal for trolling or catching wiring without using additional anchors.
- ⛽ No smoke Ensures that your new boat is not covered with a layer of oil and the things in the haunduk will remain clean.
- 🔧 Engine resource exceeds the performance of two-stroke engines by 1.5-2 times, subject to timely oil change.
Maintenance and routines
A four-stroke engine requires more attention to the lubrication system than a two-stroke engine. The first and most important procedure is to replace the engine oil. After the first break-in (the first 10 hours), the oil must be replaced, since it contains metal shavings from laundry parts.
Replacement is made every 50 hours or once a season, whichever comes first. four-stroke or automotive oils of appropriate viscosity (usually 10W-30 or 10W-40), but it is better to adhere to the recommendations of the manual.
⚠️ Warning: Never leave the engine with waste oil inside the crankcase for the winter. Acids in combustion products can destroy the internal surfaces of the engine during downtime.
An air filter also requires regular attention; in dusty roads or sandy beaches, it must be blown and cleaned more often; a clogged filter leads to enrichment of the mixture and a drop in power; the spark plug is recommended to be checked every 100 motor hours, cleaning the stain and adjusting the gap.
☑️ Seasonal engine maintenance
Comparison with two-stroke analogues
The eternal debate is, which is better, 2T or 4T? For a 4bhp, the arguments shift to four-strokes. Two-strokes only win in weight and price, but when you calculate the total cost of ownership, including buying gasoline and oil for 3-5 years, the four-stroke is more profitable.
Two-stroke engines require regular replacement of lower unit oil (in gearbox) and control of the mixture. Yamaha 4bhp. It eliminates mixing, but it requires monitoring the oil level in the crankcase, and you have to check the probe before each outing, which takes 10 seconds, but saves the engine from bullying.
Transportation is another important nuance: older two-strokes were often not allowed to be put on their side. Modern four-stroke Yamahas also have limitations, but they are less critical. However, it is recommended to use special carts for transport in the trunk of a passenger car or to keep the engine strictly vertical if the design of the boat allows it.
The four-stroke engine pays off for 2-3 seasons of active operation due to fuel savings and no oil consumption for carbon monoxide.
Typical malfunctions and ways to eliminate them
Despite the high reliability, the equipment can fail. One of the common problems is getting water into the fuel system. If the engine starts to sneeze or stall, first of all, check the fuel filter and the cup under the pear. The water is heavier than gasoline and accumulates at the bottom.
The problems with starting can be related to the spark plug: if it is black and wet, the mixture is too rich or weak spark; if the white one is poor, which is dangerous for a piston one; Regular visual inspection of the candle helps diagnose engine operation without disassembly.
Another common situation is a cut spin of a propeller, which is a safety element that breaks when the screw hits a hard object, saving the gearbox from breaking down. Always carry a spare stycht and tools to replace it.
⚠️ Warning: If the engine stopped gaining momentum after hitting an obstacle but continues to work, do not try to gas. Perhaps the propeller or shaft is damaged, which can lead to the destruction of the osteoils and water entering the gearbox.
Frequently Asked Questions (FAQ)
Can this motor be transported on the side in the trunk of the car?
The manufacturer does not recommend long-term transportation on the side, as oil can leak into the combustion chamber or leak through the sapoon. However, short-term transportation (up to 15-20 minutes) is permissible if you put the engine on the right side (from the exhaust side) or strictly vertical.
Which petrol is better to fill: 92nd or 95th?
The Yamaha F4 engine is designed to work with gasoline with an octane number of at least 92 (according to the research method). The use of 95th gasoline is permissible and can positively affect detonation resistance, but it is not strictly mandatory, the main thing is freshness of fuel and no alcohol additives.
Do I need to dilute the gasoline with oil for this engine?
Absolutely not! It's a four-stroke engine. It puts clean gasoline in the gas tank. It puts the oil separately into the engine crankcase through a special filler hole, like in a car, and mixing the gasoline with the oil will cause the candles to coking, the piston to burn, and the engine to fail.
How often should you change the oil in the gearbox?
The oil in the gearbox (dadewood) is recommended to change once a year or every 100 motor hours. When replacing, pay attention to the color of the oil: if it is colored "coffee with milk", then the water through the glands has got into the gearbox and they need to be replaced urgently.