Choosing a power unit for a boat is always a search for a balance between power, reliability and economy, and that is why. outboard motor yamach 55 two-stroke This model has long been a workhorse for medium and heavy inflatable boats, as well as for small flat-bottomed boats, and unlike today's four-stroke counterparts, the two-stroke scheme provides lower weight and higher specific power, which is critical for full-load plane.
Many owners value this technique for its simplicity of design and maintainability in the field. Yamaha 55 For commercial use, fishing in hard-to-reach places, or just for a quick ride on weekends, understanding the nuances of its work will be a key factor in durability. Let's take a look at what lies beneath the hood of this legendary "Japanese" and whether it is worth your investment.
It's worth noting that the used motor market is full of offers, but finding a really well-groomed instance is becoming increasingly difficult. carburetor And compression of cylinders will avoid costly mistakes in the purchase, and in this article we will not just list the dry numbers from the manual, but will analyze the real experience of operation.
Technical specifications and design features
At the heart of the unit is a two-cylinder, loop-blown engine designed by Yamaha engineers to ensure stable traction at all speeds, with a displacement of 933 cubic centimeters, which, when boosted, gives the claimed 55 horsepower. It is important to understand that the actual power on the propeller may vary slightly depending on the fuel quality and the setting. Mikuni carburetorswhich are installed on this model.
The ignition system here is electronic, CDI (Capacitor Discharge Ignition), which eliminates the need to adjust the gaps of the candles and replace the contact groups, as was the case with old Soviet engines. switchboard and hall-sensor The engine weight in running order (no fuel or oil) is about 84 kilograms, making it heavy enough to carry by hand, but acceptable for mounting on a thorn of a boat 4 to 5 meters long.
The secret to high traction
Why are 55 forces pulling better than some 60-horsepower analogues?: Yamaha engineers in designing this model relied on increased piston stroke and optimized gas distribution phases. This shifted the torque shelf to the lower rpm range, resulting in a boat faster to go to the plane, even if it is overloaded with equipment or passengers.
The exhaust system deserves special attention, because the exhaust gases are discharged through the screw hub, which significantly reduces noise and vibration at low speeds, which makes fishing more comfortable without scaring the fish with a loud hum. At full speed, the characteristic two-stroke sound becomes dominant, but it is perceived by many as a sign of good operation of the mechanism.
- 🚀 Power: 55 hp at 5500 rpm, which provides excellent acceleration dynamics.
- ⚖️ Weight: About 84 kg, which requires a reliable fastening of the transom.
- 🔧 Launch system: Manual starter (in basic versions) or electric starter (depending on the modification of the year of release).
- 🌊 Cooling: Forced water, water intake is carried out through a water intake in lower unit.
Fuel consumption and efficiency of operation
The issue of fuel appetite is always acute, especially given the rise in gasoline prices. Two-stroke engine It naturally consumes more fuel than a four-stroke sibling, because of the nature of the working mixture, where some of the gasoline is burned in the exhaust system. For the Yamaha 55, the average flow rate at full gas is about 20-22 liters per hour, but at cruising speed (about 3,500-4000 rpm), it decreases to 12-14 liters.
The economy depends on the quality of the mixture, if the carburetors are shot down or the jelly-clears are wrongly selected. fuel It can grow by 15-20% and the engine will start to run unstable, and using modern oil for two-stroke engines (TC-W3) in a ratio of 1:50 (for newer models) or 1:40 (for older versions) reduces the carbonation and smoke of the exhaust.
⚠️ Attention: Never use pure gasoline without adding oil! Even short-term clean-fuel operation will lead to bullying in the cylinders and the destruction of crankshaft bearings. The mixing proportion must be observed with apothecary precision.
To calculate the power reserve, you need to take into account not only data-sheet figures, but also real conditions: the presence of a negative wind, current or excitement. Fuel tank As standard, it usually holds 24 liters, which, when cruising quietly, provides a reserve of 80-90 kilometers. For long-distance crossings, experienced water engines recommend installing an additional remote tank.
Maintenance and maintenance
Resource Yamaha 55 The owner is disciplined in matters of maintenance. the Regulations prescribe the replacement of the transmission oil After the first 10 hours of running, and then every 100 hours or once a season, visual inspection of the oil for emulsion (blush plaque) allows you to detect the wear of the daydvut oil glands in time and prevent expensive repairs of the gearbox.
Ignition plugs require cleaning and checking the gap every 50-100 hours. Black colored carbon indicates a rich mixture, white indicates a poor, and brown indicates an optimal operation. You also need to regularly lubricate all lubrication points specified in the manual, using a special syringe for consistent lubrication. row-shaftReplacing them requires a decommissioning of the data.
☑️ Seasonal outboard motor TO
The cooling system requires fresh water washing after each exit to salt water or into muddy bodies of water with a lot of suspension. Clogging the cooling shirt with shells or sand is a sure way to overheat and deform the cylinder head.
- 🛢️ Oil to gearbox: Change at least once a year, even if the mileage is small.
- 🔥 Candles: Use only manufacturer-recommended (usually NGK) products.
- 🧹 Washing: Mandatory after operation in salt water.
- 🔩 Fastening: Check the tightening of the DaydWut bolts to the Daydwood.
Comparison with competitors and modifications
In the used motor market Yamaha 55 The main advantage of Yamaha is higher maximum power and, as a result, better traction at high speeds. Tohatsu, in turn, is often praised for slightly lower fuel consumption and less vibration, but in terms of acceleration dynamics, the Yamaha 55 often wins over 50-horsepower competitors.
There are several modifications to this model, differing in the year of release and the country of assembly. Older versions may have a ignition system with a interrupter-distributor, while new ones are equipped with a fully electronic system.
| Parameter | Yamaha 55 | Tohatsu M50 | Mercury 50 |
|---|---|---|---|
| Power (hp) | 55 | 50 | 50 |
| Weight (kg) | 84 | 76 | 82 |
| Workload (cm3) | 933 | 853 | 798 |
| Carburetors | 2 | 2 | 2 |
When choosing between these models, consider the availability of parts in your area. Yamaha The service network is usually wider and the parts catalog numbers are easy to find online, but if you care about every kilogram of weight, Tohatsu may be a more attractive option, albeit with a loss of 5 horsepower.
When buying a used motor, be sure to ask the seller to start it on land (in a barrel of water). Pay attention to the color of the exhaust: bluish smoke is the norm for a two-stroke, but black or gray thick smoke indicates problems with oil or piston.
Typical malfunctions and methods of their elimination
Despite the reliability, outboard motor yamach 55 two-stroke One of the most common problems is loss of spark, and the first thing to do is to check the candles and the high-voltage wires, and if there's no spark on all cylinders, you're likely to fail the switch or the Hall sensor, and diagnosing those elements requires a multimeter and a knowledge of the circuitry.
Another common problem is the leakage of the crankshaft coils, which causes air to suck into the crankcase, impoverish the mixture and, as a result, overheat the pistons, which can be a symptom of idling and difficulty starting a hot engine, replacing the coils is a laborious procedure that requires complete disassembly of the engine, so it is better to trust it to professionals.
⚠️ Attention: If the engine suddenly stalls and doesn't start, don't turn the starter indefinitely. Check for sparks and fuel. Trying to start a flooded engine can lead to hydraulic shock and rod breakage.
Carburetation problems are often caused by poor fuel quality, tar deposits clog up the jelly, which disrupts the mixing, in the field you can try to blow out the system, but full cleaning is possible only with the removal and disassembly of the carburetors, using a fuel filter-sludgeon significantly prolongs the life of the fuel system.
Tips for running a new or restored engine
The right break-in is the key to a long engine life. two-stroke This process is critical because it's a piston ring lapping to the cylinder walls. It takes about 10 hours to run the Yamaha 55. It's not recommended to run full gas in the first hours. It's optimal to run at variable speeds that are not more than 70-80% of the maximum.
It is important to use a quality rolling oil, which has increased lubricating properties, but burns without forming hard soak. After the first 10 hours, you need to replace the oil in the gearbox and check the tightening of all bolt joints, since the vibration of the workout could weaken them. It is also recommended to replace the spark plugs after running.
The success of the break-in depends not on speed, but on the variety of loads, the engine must work at idle, medium, and increased (but not maximum) speeds in different cycles.
Do not ignore the temperature during break-in. The engine should not run idle for a long time (more than 5 minutes) without load, as this can lead to local overheating and rings. If you feel that the engine is not pulling or is running intermittently, it is better to stop the break-in process and find the cause.
FAQ: Frequently asked questions
Which petrol is best used for Yamaha 55: 92nd or 95th?
The manufacturer recommends that gasoline with an octane number of at least 90 (according to the research method), which corresponds to our AI-92. The use of AI-95 is permissible, but does not provide significant advantages in power for an atmospheric two-stroke, but only increases the cost of operation, the main thing is the quality of fuel and the absence of impurities.
How often should you change the oil in the gearbox?
The oil in the gearbox is recommended to be changed after the first 10 motor hours (after running), and then every 100 motor hours or once a year, preferably before winter storage, which will help to detect water entering the gearbox and preserve the lubricating properties.
Can this motor be used in salt water?
Yes, the Yamaha 55 has anti-corrosion coating and anode protection (zinc or aluminum) to allow it to be operated in salt water, but it is a must to wash the cooling system with fresh water after each outing.
Why does the engine smoke at idle speed?
Two-stroke engines always smoke more than four-strokes. At idle speeds, combustion is less efficient, so the smoke may be more noticeable. If the smoke becomes black and caustic, check the adjustment of the carburetor (rich mixture) or the quality of the oil. If the smoke is white and thick, perhaps water or oil from the gearbox enters the combustion chamber.