Operation of water equipment requires the owner not only management skills, but also a deep understanding of the mechanics of his equipment. Mercury's 15th motor The HP is well-deservedly considered one of the most popular engines for small craft due to its reliability and simplicity of design, but even the most advanced mechanism requires regular attention, especially if it operates in an aggressive aquatic environment.
Timely maintenance avoids costly repairs and ensures that your walk or fishing isn’t marred by a sudden breakdown. In this article, we’ll take a look at all the routine steps you can do yourself in a garage or on the shore.
Before proceeding with any manipulations with the engine, you need to make sure the safety of the workplace. Mercury 15 It is a two-stroke unit (in most old and modern models of this line), which operates with high temperatures and the use of combustible mixtures.
Regular work and periodicity of the
The manufacturer clearly defines service intervals, the neglect of which may lead to loss of warranty or shorten the life of the units. Mercury 15 There are concepts of "roll-in" and regular seasonal maintenance, and primary oil replacement and fastener inspection are critical after the first 10 hours or one month of operation.
The maintenance is divided into every 50 or 100 hours, and the annual preservation, and it is important to keep a motorcycle watch journal, because the visual assessment of the oil condition is not always objective. Two-stroke engine works in a rigid temperature regime, and the combustion products of the mixture actively affect the lubrication of the gearbox and the condition of the piston group.
Many owners mistakenly believe that if the engine is running smoothly, you don't have to climb it. This is a dangerous misconception. Hidden defects, such as microcracks in the omentums or wear of the impeller pump, can manifest at the most inopportune moment. potential threats before they become fatal.
Replacement of oil in the gearbox: step-by-step instructions
One of the most important procedures is to replace the transmission oil in the lower gear, and the water that gets inside the gearbox can destroy gears and bearings in a matter of hours, due to the lack of lubrication and corrosion. Mercury 15 A special oil is used for gearboxes, usually SAE 90 or 80W-90 labels.
The replacement process starts with the engine being placed in a strictly vertical position, so that the oil glass is at the bottom and the level is correct when filling. Unscrew the bottom drain screw, and then the top vent screw. The old oil must leak out completely.
If it's a coffee with milk or an emulsion, it means that water has entered the gearbox, it's a signal that the ossels of the switching rod or the paddle shaft are not working, and if you don't need to change the oil, you need to have the seals defective and replaced.
☑️ Checking the gearbox
The gearbox is filled from the bottom up, using a special syringe pump. The oil is fed into the bottom hole until it flows out of the top hole. Only then, without removing the nose of the syringe, the top screw is twisted, then the syringe is quickly removed and the bottom screw is twisted.
Cooling system and replacement of impeller pump
The water cooling system is the heart of your motor's temperature. Mercury 15 It's implemented through a rubber impeller, which over time loses elasticity, cracks or just wears off, and overheating of the engine is one of the most common causes of jamming of the piston group.
Replacing the pump impeller requires partial disassembly of the bottom of the motor. You need to remove the water jacket casing, disconnect the lower unit (leg) from the middle part. It is important not to lose the pads and not damage the rubber seals of the lower unit when you disconnect. Old impeller often crumbles when you remove, so act carefully.
⚠️ Warning: Never start the engine without a submerged lower unit part in the water or without connecting to the forced water supply system ("soul"). Dry work, even for 10-15 seconds, is guaranteed to destroy the new impeller and can deform the seat.
When assembling the pump assembly, be sure to lubricate the inner walls of the body and the impeller with soap solution or special lubrication, which will allow it to turn on the first run without a bully. Also check the condition of the thermostat: it should open when heated and close tightly in the cold state.
How to check the thermostat without removing?
Lower the thermostat in a pot of water and heat it with a thermometer, the valve should start opening at the temperature indicated in the manual (usually about 60 ° C). If it is stuck or does not hold pressure, replace it.
Fuel system and carburetor
The quality of the fuel mixture directly affects the capacity and resource Mercury 15Because it is a two-stroke engine, gasoline is mixed with oil in a ratio of 1:50 (for modern models) or 1:25 (for older versions), using poor-quality oil or breaking proportions leads to the formation of soak and exhaust windows.
The carburetor requires periodic cleaning, especially if the engine has been out of work for a long time. The fuel has the ability to evaporate, leaving resinous deposits in the chicklers. For cleaning, it is better to use special aerosols-cleaners of the carburetor, which dissolve the deposits without mechanical intervention.
The carburetor is adjusted by the screws of quality and quantity of the mixture. A properly tuned motor must confidently keep idle and react sharply to the opening of the throttle without "failures." If the motor stalls with sharp gas, it may be too poor, which is dangerous for a piston.
| Parameter | Meaning/Action | Tool. |
|---|---|---|
| Idle move | 950 ± 50 rpm | Tachometer |
| Candle gap | 0.9. 1.0 mm | Squirt |
| The moment of candle tightening | 25-30 Nm. | Dynamometer key |
| Proportion of mixture(s) | 1:50 (2%) | Measuring capacity |
Electrical equipment and ignition system
Secure launch. Mercury 15 It's not possible without a proper ignition system, and the basic elements are spark plugs, high-voltage wires, ignition coils (or magdinos), and sensors. A candle inspection can tell you a lot about the state of the engine: black plaque indicates a rich mixture or excess oil, white indicates overheating or poor mixture.
Check the tips of candle wires. In high humidity, the contacts oxidize quickly. Clean the contacts and treat them with a special wiring lubricant that pushes water out and prevents corrosion, which is especially true for motors that are stored in unheated spaces.
If the engine doesn't start well or Troit, check the spark. Unscrew the candle, thread it against the mass of the engine and pull the starter sharply. The spark should be bright blue and punch the gap with a characteristic crack. A weak spark can be the result of a discharged battery (for an electric starter) or a malfunction of the switch.
When you store the engine in the off-season, unscrew the spark plugs and pour 5-10 ml of engine oil into the cylinder. Rotate the crankshaft several times so that the oil spreads across the walls, and spin the candles back. This will prevent the cylinder from corrosion.
Preservation for winter
Proper preservation is a guarantee that in the spring you do not have to waste time on repairs. After the navigation is over, you need to completely develop the fuel from the carburetor or drain it. The remains of gasoline evaporate during the winter, leaving the resins that clog the jelly.
The motor should be thoroughly washed with fresh water to remove salt and dirt, then grease all external movable connections, gas control cables and turn lower unit. Mercury 15 It is better in an upright position to water completely glass from the cooling system.
Be sure to treat the outer surfaces with an anti-corrosion spray. Pay special attention to the places of paint chips in the lower unit. The metal that comes into contact with water rusts very quickly, and in the spring you will have to clean the rust and paint again.
⚠️ Warning: Do not store the motor in a sealed case if it is wet, this will create a greenhouse effect and accelerate corrosion, let the engine dry completely before packing or use breathable covers.
Frequent malfunctions and methods of their elimination
Even with quality maintenance, there can be typical problems, such as difficulty starting often due to compression failure or fuel supply problems. If the compression is normal and the engine is not starting, check for sparks and fuel in the float chamber.
Vibration at high speeds can indicate damage to the propeller or hitting a foreign object (swings, nets) on the shaft. Leaf wound on the shaft can damage the omentum, which will lead to water entering the gearbox. Always inspect the screw after every fishing in overgrown places.
The loss of power is often due to contamination of the exhaust system (coar in the muffler) or improper adjustment of the carburetor, and it is also worth checking the condition of the fuel filter-sludge, which can be clogged with garbage from the tank.
Timely replacement of the impeller pump (once in 2-3 seasons) costs 10 times cheaper than replacing the piston group after overheating.
FAQ: Frequently asked questions
Which oil is best used for a mixture with gasoline in Mercury 15?
For modern two-stroke Mercury engines, it is recommended to use semi-synthetic or synthetic oils labeled TC-W3. They provide better lubrication, smoke less and form less carbon than mineral counterparts.
Can I use AI-95 gasoline?
Yes, the use of AI-95 gasoline is allowed and even preferred to prevent detonation, the main thing is that the gasoline is fresh, and it is not recommended to store the ghee mixture for more than one month, since it loses its properties.
Why does the engine stop at idle speed?
The most likely causes: clogging of the idle jeeler of the carburetor, sucking excess air through the gasket of the intake manifold or improperly exposed screw of the quality of the mixture.
How often should the fuel filter be changed?
The fuel filter-sludge (if it is built into the motor) or the external filter is recommended to be changed or washed every season. If you use a transparent filter, watch for water and dirt on the bottom of the bulb.
What to do if water gets into the gearbox?
Stop using immediately. Plug the emulsified oil, rinse the gearbox with pure oil or diesel (gently), replace the oedes (usually the oal of the paddle shaft and switching rod), pour new oil and test the pressure tightness before going out on the water.