Operating a outboard motor in an aggressive aquatic environment, whether fresh rivers or salty seas, inevitably leads to the destruction of the paintwork. Tohatsu Often, after several seasons, chips, scratches and corrosion patches appear on the hood, ignoring these defects can cause serious damage to metal assemblies and reduce the market value of the unit during resale.
Tohatsu’s high-quality outboard paint not only serves an aesthetic function, covering up traces of operation, but also serves as a powerful barrier against electrochemical corrosion. The correct chemical composition of the coating is able to withstand high temperatures, vibration and constant exposure to ultraviolet light. In this article, we will discuss in detail how to choose the best material and paint yourself, returning the engine to its original appearance.
Requirements for paint materials for water equipment
Choosing paint for an outboard motor is not just a matter of color, it's a complex technical challenge. Unlike car enamels, sea coatings must have increased adhesion to the aluminum and magnesium alloys that make the gearbox and diewood bodies. Conventional nitro-emalee or acrylic paints will quickly peel off under the influence of salt water and temperature changes, leaving the metal defenseless.
Modern industrial enamel for boat-engine The most popular polyurethane two-component compounds, which after polymerization form an extremely strong, chemically resistant film, are also widely used epoxy soils and finishing alkyd-based coatings, which are easier to apply but require more time to dry.
⚠️ Warning: Never use paints that are not intended to come into contact with water or are not marked "Marine"; conventional car enamels may contain components that react with the engine's aluminum alloys, causing accelerated corrosion.
The most important parameter is the heat resistance of the coating. The cylinder head and exhaust system heat up to high temperatures during operation. If you apply heat-resistant paint only to these units, and the rest of the body is normal, then after the season you will get an uneven faded appearance. So professionals recommend using a single system of materials from one manufacturer for the entire product.
Surface preparation and corrosion removal
The success of painting depends on the quality of surface preparation, and even the most expensive Japanese paint will not be kept on dirty, oily or oxidized metal. The first step is always to thoroughly wash the engine using special degreasers, and remove all traces of oil, fuel, lubrication and algae.
☑️ Checklist for surface preparation
After cleaning, you have to do a machining step, and all the corrosion sites need to be cleaned to pure metal, and you can use sandpaper, metal brushes, or a sandblaster for complicated cases. Tohatsu there are deep chips or shells from corrosion, they should be shpatted with an epoxy composition resistant to water.
Surface grinding is a critical process. Smooth metal will not provide good adhesion, so the surface must have an even risk (roughness).
⚠️ Attention: When grinding, try not to overheat the thin-walled elements of the motor body, as this can cause deformation of aluminum. Use reciprocating movements and moderate pressure.
The final step of preparation is final degreasing with silicone. Rub the surface with pure rags soaked in solvent and proceed immediately to priming to avoid dust precipitation or re-oxidation.
Color selection and material compatibility
Tohatsu motor owners often seek to restore the factory dark blue that is the brand’s trademark. However, the market offers many shades and choosing the right tone requires careful attention. The original Tohatsu color is often called “Tohatsu Blue” or “Dark Blue”, but different paint manufacturers (Nissan, Mercury, Johnson) shades can vary.
Codes of the original Tohatsu colors
For color selection, you can use the original color codes, for example, for classic dark blue, a code close to the RAL 5003 or special catalog numbers from marine paint manufacturers such as Nippon Paint are often used. The exact shade can vary depending on the year of the engine.
When choosing a system of materials (soil, paint, varnish), it is extremely important to observe the compatibility of chemical components.
- 🎨 epoxy It is ideally placed on aluminum and provides maximum anti-corrosion protection, but requires overlapping with compatible enamel.
- 🛡️ Acid soil (Vixen) It is used for primary processing of non-ferrous metals, creating a chemical bond with the surface, but on top of it, insulating soil is necessary.
- 🔫 Polyurethane enamel - the best choice for the finish layer, with high elasticity and resistance to shocks.
If you plan to paint the engine fully, it is better to purchase a ready-made touch-up kit or to encase professional marine paint in a specialized studio. Self-coloring "by eye" often leads to a disappointing result when the lid of the lower unit is different in shade from the lower unit.
Coating technology
The process of applying paint to the outboard motor requires compliance with temperature and humidity. The optimal temperature for work is from +15 to +25 ° C. At lower temperatures, the paint may not spread correctly, forming a "shagrain skin", and at high ones - dry too quickly, before having time to form a smooth film.
The application of the primer layer should be thin and uniform. Do not try to immediately cover all defects with a thick layer - this will lead to leaks. It is better to apply 2-3 thin layers with interlayer drying, specified by the material manufacturer. After drying the soil, the surface often requires light grinding with fine-grained abrasive (P400-P600) to remove dust.
The finishing coating is applied similarly.
The distance from the torch of the spray gun to the surface should be 20-25 cm.
Movements should be smooth, parallel to the surface, with overlapping the previous passage by 50%.
If you use an aerosol spray, warm it in warm water (not hot!) to a temperature of 30-35 degrees before starting work, which will improve the spraying and fluidity of the paint, making the layer more even.
Table of comparison of coating types
For convenience of choice, we give a comparative description of the main types of coatings used for the restoration of Tohatsu engines.
| Type of coating | Resistance to water | Difficulty of application | Time of complete polymerization | Price. |
|---|---|---|---|---|
| alkyd enamel | Medium | Low. | 24-48 hours | Low. |
| Acrylic lacquer (2K) | High. | Medium | 7 days | Medium |
| Polyurethane (2K) | Very high. | High. | 7-14 days | High. |
| epoxy | Maximum | Medium | 24 hours. | Medium |
As can be seen from the table, two-component polyurethane systems require more time and skills, but provide the best result for intensive operation.
Drying and finishing
After the last layer of paint is applied, the polymerization process begins, and it's important to understand the difference between drying out to the stick and full polymerization. The motor may appear dry after a few hours, but the chemical strength of the coating is gained within a week or more, during which time it is absolutely impossible to allow contact with water, especially salt water.
The full operational strength of the coating is achieved only after final polymerization, which can last up to 14 days depending on the temperature and type of paint.
Infra-red lights can be used to speed up the process, but the surface temperature should not exceed 60°C, so as not to cause the solvent to boil inside the layer. After drying completely, the surface can be polished with car polish to remove fine shaking and give a deep gloss.
Frequent mistakes in painting
Many beginners, in an effort to save or speed up the process, make mistakes that negate all efforts, one of the most common is to paint on wet or cold metal, and the condensation that comes after painting will lead to the peeling of the coating with bubbles after the first operation.
Also often ignored is the need to use the right solvents: if you dilute the paint too quickly with a solvent that evaporates, it will not have time to spread; if it is too slow, it will flow.
For Tohatsu engines with their complex geometry and many cooling ribs, it is critical to choose the correct viscosity of the paint so that it flows into all the indentations, but does not form droplets on the edges.Another mistake is that there's no protection for the inner cavities, and the beauty of the lower unit outside, they forget to treat the inner cavities with anticores, where condensation accumulates even more actively.
FAQ: Frequently asked questions
Can I paint a Tohatsu engine with a regular car paint?
Technically, it's possible, but it's not recommended. Car paints are not designed to be immersive and salty, they'll quickly lose their luster and start flaking away. Better to use specialized sea enamel.
Do I need to remove the engine from the boat for painting?
It is advisable to remove the motor and remove all plastic casings, gas handles and electrical components, paint the assembled motor is extremely inconvenient, there is a high risk of painting the moving parts and damaging the electrician with solvents.
How much dried paint for the outboard motor before launching?
The minimum time before contact with water is 7 days at a temperature of +20 ° C. For complete polymerization and maximum chemical resistance, it is recommended to wait 14-20 days.
How to remove small scratches on lower unit without a full repainting?
For small scratches, you can use special restoration pencils or two-component epoxy markers of a selected color. Clean the scratch, degrease and gently apply the composition, then polish.