Operating aquatic machinery requires not only the owner's control skills, but also a deep understanding of the technical nuances of the power plant. two-stroke outboard motor It depends on the quality and composition of the fuel mixture that is being poured into the tank, and improper fuel preparation is the fastest way to disable expensive equipment, often irreversible.
The process of mixing gasoline and special oil seems trivial, but it is here that many errors lie, leading to overheating of the piston group or, conversely, to coking candles and silencers. Two-stroke cycle This work involves burning oil with the fuel, lubricating rubbing parts for a short time, so the balance of components should be perfect. In this article, we will detail the chemical and physical aspects of preparing the mixture to keep your motor running for years to come.
It's important to understand that there's no universal magic ratio that's right for all engines in nature. Yamaha, Tohatsu or MercuryThe company has established its own tolerances based on the design of the crank-shaking mechanism and the cooling system, and ignoring these requirements is equivalent to playing Russian roulette with the technical condition of your vessel.
Principle of operation and the need for mixing
Fundamental difference two-stroke The four-stroke engine is basically the absence of a separate crankcase lubrication system, and in a classic ICE, oil circulates in a closed loop, washing the parts, whereas in a 2T engine, the lubrication occurs directly when the fuel-air mixture passes through a crankcase, which is why the oil must be dissolved in gasoline beforehand.
When you compress the mixture in the cylinder, the oil film settles on the walls, the piston and the bearings, allowing you to slide. If the oil concentration is insufficient, you will have dry friction, leading to instant bully and wedge, and excess oil leads to the formation of soak, which disrupts heat transfer and can cause you to lose weight. ignition.
Modern technology has made it possible to create oils that burn almost without a trace, minimizing harmful emissions and sediments. TC-W3 The mechanical mixture, when it enters the carburetor, is sprayed with a nozzle, and the quality of this fog directly affects the efficiency of combustion.
⚠️ Attention: Never try to run a two-stroke engine on pure gasoline, even for a short time to "check"; the lack of lubrication in the first seconds of operation will lead to fatal damage to the crankshaft bearings.
Understanding the thermodynamics of the process helps you understand the importance of every gram of added oil, and the temperature in the combustion chamber reaches thousands of degrees, and the task of the oil additive is to withstand these loads without losing its properties until the moment of combustion, which is why the use of conventional motor oils for cars is strictly prohibited.
Selection of components: gasoline and specialized oils
The quality of the final mixture depends on the original ingredients. leadless The use of fuels with a higher octane number (AI-95, AI-98) often makes no sense and can even be harmful due to the content of excess additives that do not have time to burn in high-speed outboard motors.
The second component is a special oil for water technology. You'll find the labels on the canisters. TC-W3 Two Cycle Water-cooled, which means that they meet the standards of the National Association of Marine Manufacturers, and they're designed to work in high humidity and cooling conditions with off-shore water.
- 🛢️ Mineral oils - are produced from oil, have a lower cost, but form more sediment and require strict adherence to the shelf life of the mixture.
- 💧 Semi-synthetic oils - compromise option, combining purified mineral bases with synthetic additives to improve lubricating properties.
- 🧪 Synthetic oils A fully synthetic substrate provides the best protection, minimal smoke and the ability to self-clean the engine from soot.
The shelf life of the finished fuel mixture is limited: gasoline oxidizes when in contact with air, losing its properties, and oil can precipitate. It is recommended to prepare a fuel volume designed for no more than 2-3 weeks of operation, unless you use special stabilizing additives.
The components and the finished mixture must be stored in special canisters of material resistant to the effects of petroleum products. Conventional plastic bottles from under water can chemically react with gasoline, which will lead to the dissolution of plastic and fuel pollution, which is critical for the use of plastics. fuel-system engine.
⚠️ Attention: It is strictly forbidden to use oil for four-stroke engines or transmission oil. They have a different viscosity and additive package, are not designed for combustion in the chamber and will cause the engine to fail.
Exact proportions: mixing table
The most critical part of the whole process is to be proportional, and you can't make a mistake in your peephole calculation, and the proportion is specified by the manufacturer in the manual, and it's usually 1:25, 1:40 or 1:50, where the first digit is part of the oil and the second digit is part of the gasoline.
For the convenience of users, we have prepared a summary table that will help you quickly determine the amount of oil you need per known volume of gasoline. Use measuring tanks with calibration to achieve maximum accuracy.
| Proportion of mixture | Oil per 1 litre of gasoline (ml) | Oil per 5 liters of gasoline (ml) | Oil per 10 liters of gasoline (ml) | Type of motor |
|---|---|---|---|---|
| 1: 25 | 40ml | 200 ml | 400ml | Old models, motors without catalyst |
| 1: 30 | 33 ml | 167 ml | 333 ml | Medium power motors (30-40 hp) |
| 1: 40 | 25ml | 125 ml | 250 ml | Modern 2T engines (Tohatsu, Yamaha) |
| 1: 50 | 20ml | 100ml | 200 ml | High-tech motors with catalyst |
When mixing, it is important to consider that measuring cups, which come with oil, often have an average scale. gauge-cylinder Or a large syringe for small dosages, and accuracy up to a gram extends the life of the engine.
If you use gasoline that has been in the canister for more than a month, its octane number may have decreased, in which case, even if you follow the proportions, you risk detonation. Always try to use fresh fuel, especially if the engine runs at high revs.
Why do the proportions change over the years?
Previously, oils were less effective and required more concentration (1:25). Modern synthetic oils allow you to make the mixture poorer (1:50), which reduces smoke and nagaroprostivovo, maintaining excellent lubrication due to improved adhesive properties.
Technology of preparation: step-by-step instructions
The mixing process requires a sequence of actions to produce a homogeneous emulsion, and just pouring components into a tank and chatting the boat is the wrong approach, which can lead to the mixture being dissected and the engine running in oil starvation mode.
First of all, prepare a clean mixing tank, which can be a special measuring canister or a separate tank. Never mix components directly in the outboard motor tank, because there is no good mixing.
☑️ Checklist of proper mixing
First, pour about half the amount of gasoline you need. Then add all the oil you need. Then shake the tank carefully so that the oil dissolves in the gasoline. Only then add the remaining gasoline and mix again.
This two-step technology avoids the situation where concentrated oil settles at the bottom and does not dissolve well in the full amount of fuel, the resulting mixture must be completely uniform, without visible oil films on the surface or (spraying).
The finished mixture is recommended to be used for a month. If you plan to store the boat longer, for example, in the winter, the tank is better preserved or to produce fuel completely.
Use a transparent mixing tank to visually control the process of oil dissolution and the absence of sediment or water at the bottom.
Common mistakes and their consequences
Even experienced water-engineers sometimes make mistakes that can be worth overhauling. One of the most common problems is confusion in units of measurement. Liters, gallons, ounces and milliliters are easily confused if you are not careful when reading the instructions for oil.
Another mistake was the old-fashioned method of mixing by eye, the proportions of two-stroke motors became much thinner with the development of technology, while for an old engine, the added oil could pass with impunity, modern oil could pass with impunity. booster It may be affected by the slightest deviation.
- 📉 Short oil. It causes overheating, piston blistering, bearings breaking down and engine wedges, and repairs are often inappropriate.
- 📈 Oil spill - causes coking candles, adhesion of soda on the piston, a decrease in power and increased exhaust smoke.
- 💧 Water intrusion Water is heavier than gasoline and settles to the bottom, getting into the carburetor at the end, which causes corrosion and unstable operation.
Also worth mentioning is the storage error: Many store the mixture in transparent canisters in light, UV light speeds up the chemical reactions of gasoline decay, store the fuel in a dark, cool place, in tightly closed containers to minimize contact with air.
⚠️ Attention: If you notice that the spark plug is constantly covered with black soda, even at the right proportion, it is possible that you are using low-quality or the wrong type of oil for your engine.
Motor break-in: a special mode of the mixture
Special attention should be paid to the period of running a new engine or engine after major repairs, during which the rubbing parts are only rubbed against each other, and the load on them is maximum. Manufacturers often recommend changing the standard proportion of the mixture for the break-in period.
Usually, the first tanks (5 to 10 liters) are recommended to add more oil, for example, use a ratio of 1:25 instead of the standard 1:40 or 1:50. This creates a thicker oil film, protecting new surfaces from microscopic and overheating in conditions of increased friction.
It is important not only to change the composition of the mixture, but also to observe the speed mode. You should not give full gas or, conversely, work at idle speeds for a long time. breaking in mode This involves variable loads: acceleration, gas discharge, medium-speed operation, which contributes to the uniform grinding of the rings and cylinder.
After the break-in (usually 10 hours of motorized hours) you need to switch to the regular proportion of the mixture. Further work on the enriched mixture will only lead to engine contamination and will not give any advantages, since the parts have already worked.
Properly break-in with an increased dose of oil is a guarantee that your engine will produce all the declared resource without loss of compression and power.
Recycling and environmental safety
The environmental issue is becoming increasingly important for water engines: residues of fuel mixture, washing liquids and old oils should never be poured into water bodies, on the ground or into sewers. Petroleum products form the thinnest film on water that blocks the access of oxygen and destroys all life.
Modern class oils TC-W3 They're certified biodegradable, but that doesn't give you the right to pour them in liters. They degrade faster than normal, but they're still a chemical contaminant at high concentrations. Take care of nature, because that's why we buy boats.
Pour waste liquids into sealed containers and take them to hazardous waste reception points. Many marinas and service centers have "workout" tanks installed. This is, but these are the little things that make up the water turbine culture.
Using a good, well-cooked mixture is not only a concern for technology, but also a contribution to the cleanliness of water bodies. Clean exhaust and the absence of oil iris film on the water at the stern are a sign of a good engine and a responsible owner.
Can I mix different types of oils and manufacturers?
Technically, you can mix both oils if you meet the TC-W3 standard, but manufacturers do not recommend this, because the chemical composition of additives can vary. In an emergency, you can add it, but for continuous use it is better to use the same brand and type of oil.
What if I poured clean gasoline and started the engine?
Turn off the engine immediately! Don't try to roll it or give it gas. If the engine has been running for a few seconds, there's a high probability of damage. You need to drain the fuel, flush the system and check the compression. You can't continue to operate without oil.
How to understand that the mixture is cooked incorrectly by the engine?
When oil is scarce, the engine starts to squeal (dry friction), loses traction and can jam. When there is excess oil, there is black smoke from the exhaust, oily soak on the candle, power drops and difficulty starting. Vibrations can also increase.
Do I need to shake the tank before each gas station?
Yes, it's a good habit. Although modern oils dissolve well, with prolonged idle boats (even during the day), micro-splitting can occur, and a slight swaying of the tank before launch ensures that a uniform mixture is fed into the carburetor.
Does the octane number of gasoline affect the proportion of the mixture?
The proportion of the oil does not directly affect the proportion of the octane number. The proportion depends on the design of the engine. However, the use of gasoline with an octane number below the recommended (for example, AI-80 instead of AI-92) can cause detonation that will destroy the engine regardless of the quality of the mixture.