Any owner of water-motor equipment sooner or later faces the need to maintain its own water-motor equipment. boat-engineOne of the most critical steps in T. T. is regular grease of lower unit, which is the syringe of slits, nuts and driveshafts, and ignoring this procedure can lead to costly repairs, corrosion and jamming of nodes. In this article, we will detail what materials are needed for high-quality lubrication, how to distinguish suitable compounds from unsuitable ones, and step by step the entire procedure.
Many beginners mistakenly believe that it is enough to fill the lubricants in the nodes with a margin, but overgreasing It's just as dangerous as not having it, and the pressure inside of lower unit can squeeze out. plumbingIt's going to get water into the gearbox and quickly break down expensive mechanics, so it's important not only to choose the right composition, but also to follow the application technology.
We will look at the main types of lubricants on the market, their compatibility with various sealing materials and the features of use on two-stroke and four-stroke engines. Understanding the chemical composition and physical properties of lubricants will help you extend the life of your engine by hundreds of hours.
Why do you need to syringe a lower unit outboard motor
The main purpose of the lubrication in lower unit is to create a protective film that prevents direct contact of metal surfaces that are subjected to high loads. drive-shaft It transfers torque from the crankshaft to the gearbox, and without proper protection, friction will quickly wear out the squirrel joints, and the lubricant also acts as a preservative, displacing moisture and blocking oxygen from the metal.
The second important function is corrosion protection, which is especially important for use in salt water. Even microscopic scratches on the shafts can become foci of rust, which, when it spreads, can destroy the structure of the metal. needle-douching creates a barrier that prevents oxidative processes.
⚠️ Attention: If you find an emulsion when you extract the lower unit, it indicates that water has entered the gearbox, and then simple lubrication will not help, you need to replace the omentums and defect the gears.
It's also worth remembering that lubricant helps remove heat from rubbing vapors, although the main heat sink in outboard motors is through a water cooling system. A properly selected material retains its properties over a wide range of temperatures, without draining when heated or solidifying in the cold.
Lubricants Requirements for lower unit
When choosing what to syringe a outboard motor, you can't rely on the principle of "only slippery." A lower unit lubricant must have a specific set of specifications that distinguish it from conventional lithium or graphite compounds. water-resistantThe material should not be washed off with water even with prolonged contact, otherwise the protection will disappear after the first trip.
The second critical parameter is adhesion, and the lubricant must be held firmly on the vertical surfaces of the shafts, and not drained by centrifugal forces at high revs. If the composition is too liquid, it will simply fly out of the slime, leaving the metal unprotected. Also important is compatibility with rubber seals: aggressive components can cause swelling or cracking. sludge.
- 🛡️ Anti-corrosion properties: Ability to block metal oxidation in an aggressive aqueous environment.
- 🌡️ Thermal stability: preservation of viscosity and structure when heated to 100-120 ° C and cooled to sub-zero temperatures.
- 💧 Hydrophobicity: complete repulsion of water and the impossibility of emulsion formation.
- ⚙️ Mechanical stability: resistance to structure destruction under high loads and shear.
Many motor manufacturers, such as Yamaha, Mercury or TohatsuThey make their own line of lubricants that are guaranteed to meet the requirements of their equipment. The use of original materials is often a condition for maintaining the warranty, but there are also high-quality third-party counterparts from brands like Liqui Moly, Mobil or Castrolspecially designed for marine applications.
Always check the lubricant packaging for "Marine" or "For Marine Engines" labels. Conventional car lubricants may contain additives that destroy non-ferrous metals and rubber seals of outboard motors.
Overview of lubricants types: lithium, disulfide and synthetic
There are many options on the market, and they can be difficult to understand, and the main division is by thickener type and base oil. lithium-greasewhich are often labeled as Li-ComplexThey have good water resistance and mechanical stability, being a versatile choice for most outboard motors of medium power.
For nodes experiencing extreme loads, lubricants with the addition of molybdenum disulfide (MoS2)They have a characteristic dark gray, almost black color, and they create a very strong film that can withstand tremendous pressures, but they are not recommended to be mixed with other types of lubricants without completely cleaning the knot.
Synthetic lubricants are the top tier of protection, and they are created using synthetic oils and complex thickeners, ensuring maximum service life and operation in extreme temperature conditions. Synthetic lubricants do not require replacement every season and can last for 2-3 years with moderate use. However, their cost is much higher, and mixing with mineral analogues is strictly prohibited.
| Type of lubricant | Basis | Water resistance | Application |
|---|---|---|---|
| Lithium (Li-Complex) | Mineral | High. | Schlitz, cardan, universal. |
| Disulfide (MoS2) | Mineral/Synthetics | Very high. | High-loaded slits |
| calcium | Mineral | Medium | Hub bearings (rare for lower unit) |
| Synthetic | Synthetic | Maximum | Extreme conditions, long interval |
When choosing a color label, you should also pay attention to the color marking, although it is not always the standard, you can often find lubricants of green, blue or red, it is important to be guided not by the color, but by the specifications specified by the manufacturer in the product passport.
Tools and preparation for the syringe procedure
Before you start, you need to prepare the workspace and tools. lubricant It is better to use a professional metal syringe with a lever mechanism, since plastic analogues often cannot create enough pressure to push thick lubrication into narrow channels.
To clean the surfaces will need rags, degreasing (for example, WD-40 Specialist Degreaser Or regular Kalosha gasoline and a brush. And also, remember to use gloves, because it's going to be very difficult to wash the old lubricant off your hands, and if you're planning on taking a full lower unit, you're going to need a set of keys and maybe a wooden bar to fix the flywheel.
☑️ Preparation for douching
If you're not shooting the whole lower unit, but you're running express service through the process holes, make sure the motor is securely attached to the transom or rack. Access to the slits should be free. Often you need to remove the locking ring or the nut fixing the lower unit, so prepare the appropriate tool in advance.
It is important to keep the work area clean. Getting sand or abrasive dust into a lubricated unit can play an abrasive role and speed up wear. If work is done outside in windy weather, try to close the work area with plastic or do the procedure in the garage.
Step by step: how to properly syringe the motor
The lubrication process depends on the design of your motor, but the overall algorithm remains similar. If you remove a lower unit, then after dismantling it and cleaning the old lubricant, you need to apply a new layer on the blades of the driveshaft, the splint of the paddle shaft and the slit nut. The lubricant should be applied evenly, filling all the grooves, but without forming huge "nozzles" that can disrupt the balance.
When using a syringe without being completely disassembled, find special oils (press oils) on lower unit, which are usually located at the bottom of the lower unit or on the gear bracket. Wipe the oil clean, insert the nose of the syringe and start slowly pumping the grease. You should see how the fresh grease starts to squeeze out the old one of the gaps.
⚠️ Attention: Don't overdo it with pressure! If the lubricant has stopped going and the new one is not coming in, don't push it too hard. It can cause the glands to rupture. It's better to repeat the procedure in a short time, when the old lubricant "goes" into the gaps.