Operating an outboard motor in an aggressive aqueous environment inevitably leads to a loss of external appeal. Salt water, temperature changes, rock and gravel shocks, and ultraviolet exposure destroy the factory paintwork, opening the way for rust. If this process is not stopped in time, corrosion can spread to the factory. crankcase and other important components, which will require expensive repairs or replacement of the unit.
Self-painting is not only a way to bring back the tidy look, but it's also a real opportunity to save a significant amount of money that you would have to pay in the service workshop. And by doing the work yourself, you get complete control over the quality of the materials used and the thoroughness of the surface preparation. enamel and compliance with application technology will provide protection for long seasons of active fishing or cruising.
In this article, we will discuss in detail the entire process: from dismantling attachments to finish polishing. You will learn what tools are necessary for quality work, what is different from painting Yamaha from Tohatsu in terms of preparation, and what mistakes are most often made by beginners, reducing the result to nothing.
Selection of materials and tools for painting
The success of the event depends on 80% on the right paint material. Conventional automotive paints may not withstand constant contact with water and salts, so it is important to choose specialized products. adhesion.
For outboard motors, two-component polyurethane or epoxy paints are considered the best choice, creating a strong chemically resistant film that is not afraid of gasoline, oil and mechanical damage, but they are more difficult to work with, since after mixing the components, the master has a limited time to apply before the composition begins to polymerize.
- 🎨 Two-component enamel - provides maximum strength and gloss, but requires accurate compliance with the mixing proportions.
- 🖌️ Alkyd paint (for example, Tikkurila) is easier to apply, dries for a long time, forming a smooth surface, but less resistant to impacts.
- 💨 Aerosol spray - suitable for local repair of small chips, but gives a less durable coating with full painting.
- 🧪 Solvent - is necessary for degreasing the surface and washing the spray gun (use only the paint recommended by the paint manufacturer).
In addition to the paint, you will need quality. primerIt's a corrosion-resistant, zinc- or chromium-resistant, and it's a junction between the metal and the finishing layer, and you can also use sandpaper of different grains (from P80 to P2000), paint tape, degreaser and personal protective equipment like a respirator and gloves.
⚠️ Warning: Never use water-based primers to paint daydvut, as they are hygroscopic and can cause aluminium underfilm corrosion.
Dismantling and primary surface preparation
Before you take on the grinder, the motor must be properly prepared. dismantling Remove the fuel hose, candle caps, lower unit (if designed), anti-cavitation stove, thermostat and any plastic casings that are not planned to be painted.
After dismantling, the engine must be thoroughly washed from dirt, silt and oil stains. Use warm water with the addition of dish detergent or special degreasing. Pay special attention to hard-to-reach places around. carburetor And in the area of lower unit, where oil accumulates often, and after washing, the surface should dry completely.
☑️ Preparation of the engine for painting
The next step is mechanical cleaning, and the old swelling and rust must be removed completely, to the pure metal, and you can use a P80-P120 abrasive grinder or chemical paint washes, and the chemical process is less dusty, but you need to be careful not to let the aggressive liquid get on the glands and seals.
| Type of damage | Processing tool | Graininess of abrasive | Purpose of processing |
|---|---|---|---|
| Deep corrosion | Metal brush/Pande | P60 - P80 | Removing loose rust to a solid base |
| Old paint. | Grinding machine/Washing | P120 - P180 | Creating Risks for Adhesion |
| Small chips. | Sandpaper | P240 - P320 | Smoothing of transitions (edge washing) |
| Finishing | Soft bar | P400 - P600 | Underground training |
Printing and shpatelling technology
After mechanical cleaning, the metal surface becomes vulnerable to instantaneous oxidation, so it must be degreased immediately. white spiritThe movement must be in one direction, so as not to smear dirt on a clean surface.
If you have deep corrosion sinks or dents on the engine body, you have to level them out. This is done with a car polyester putty, and you put it in a thin layer, and you try not to create too much thickness, because when you heat the engine, the putty can crack, and when you dry, you grind the putty, aligning it with the main body profile.
Should I lay a putty?
Putty is a porous material that absorbs moisture, and if you put the paint directly on it, after a while, a bubble forms in this place, so the putty areas must be soaked in 2-3 layers, insulating from the atmospheric influence.
Soiling is a critical step. Acid (phosphate) soil creates a chemical bond with aluminum, preventing oxidation, and acrylic filler soil levelles microrelief. Apply the soil in thin layers with intermediate drying according to the manufacturer's instructions. Usually 2-3 layers are required. After drying, the soil is sanded with fine abrasive (P600-P800) to a perfectly smooth state.
⚠️ Warning: The time of interlayer drying of the soil cannot be reduced by artificial heating (dryer), unless indicated in the instructions, as this can lead to boiling of the solvent and the formation of pores.
Finishing process
Painting a outboard motor requires a clean, well-ventilated room without dust. The optimal air temperature is from +15 to +25 ° C, the humidity is not more than 75%. Before starting work, the paint must be thoroughly mixed, and if a two-component composition is used, mixed with a hardener in strictly specified proportions and withstand the induction time (usually 10-15 minutes).
Paint is best applied with a spray gun with a nozzle diameter of 1.3-1.4 mm. Keep the tool perpendicular to the surface at a distance of 20-25 cm. Movements should be smooth, intercepting the previous passage by 50%. The first layer is made thin ("fog") to improve the grip. The subsequent 2-3 layers apply more saturatedly, but avoiding the undertick.
- 🔫 First layer - thin, serves for adhesion, may look translucent.
- 💧 Second layer - the main, forms color and cover.
- ✨ Third layer - finishing, provides depth of color and gloss.
If you use an aerosol spray, the technology doesn't change, but it's harder to control the thickness of the layer. You have to hold the canister strictly upright and move it constantly, not staying in one place to avoid orange peeling or leaking. Shake the canister between aisles.
To get the effect of "metallic" or "pearl" after drying the base layer of paint, be sure to apply 2 layers of transparent lacquer (2K varnish). This will protect the pigment from burnout and give depth to the color.
Drying, assembly and protection of the coating
Full polymerization of modern enamels takes anywhere from 24 hours to several days. Although the paint may dry out in an hour, take your time to assemble the engine. Early assembly can lead to fingerprints or damage to the edges of parts. It is ideal to let the engine stand in a warm room for at least 24-48 hours before operation.
Once the paint is dry, you can start the assembly. Install all attachments, check the tightening of the bolts. In places where the paint was damaged during assembly, it is advisable to apply a small drop of paint or transparent varnish with a brush to prevent corrosion. It is also recommended to treat visible metal parts (bolts, nuts) with lubricant for outboard motors.
To extend the life of a new coating, use protective waxes or polishes for outboard motors. Regular fresh water washing after each outlet on salt water is a mandatory rule. Do not use aggressive brushes or abrasive powders when washing, so as not to scratch fresh varnish.
⚠️ Warning: First start of the engine after painting with caution. Make sure that exhaust gases do not fall on freshly painted surfaces of the daydvut until they are finally hardened, otherwise color change or clouding may occur.
Frequent mistakes and how to avoid them
Even with quality materials, the result can be spoiled by a technology failure, and one of the most common mistakes is not enough degreasing, and the residue of oil or silicone causes the paint to flake off after a while with stockings or craters (fish eye).
Another problem is painting in high humidity or low temperature, moisture condensing on cold metal or falling into a colorful torch causes varnish clouding (the “bleaching effect”), and it is also dangerous to apply thick layers of paint in the hope of saving time, guaranteed to wrinkle the coating and long drying times.
The quality of painting depends on the surface preparation 90%, and saving time on grinding and degreasing always leads to a defect that can not be repaired without complete rework.
Ignoring material compatibility is also fatal, such as applying nitro-paint to bitumen soil or acrylic to oil will cause a chemical reaction and swelling, always using materials from the same system or running a compatibility test in an inconspicuous area.
Can I paint my motor without taking it off the boat?
It is not recommended. Painting requires access from all sides, including the bottom of the daydwoot and the area around the active screw. In addition, getting paint on the propeller, lower unit or the attachments to the transom is unacceptable - this can disrupt the balance or cause jamming of the knots. The motor needs to be removed.
How much paint does the outboard motor dry?
The drying time depends on the type of paint and temperature. Aerosol enamel dries to a stick in 30-60 minutes, but the full strength is gained after 24 hours. Two-component epoles can dry up to 12 hours before touch, and full polymerization takes up to 7 days. In the cold season, the time increases.
Do I need to take down lower unit for painting?
Yes, it's necessary. lower unit is the most vulnerable part, exposed to shock and corrosion. You can't paint it without removing it properly. Also, there are often pockets of corrosion under the lower unit that need to be cleaned up. lower unit also allows you to check the condition of the glands and the gear rod.
What is the difference between a two-stroke engine and a four-stroke?
There's no fundamental difference in painting technology, but four-stroke motors, like this one, Honda or Mercury 4T) have a more complex cooling system and more plastic casings that often do not require painting. Tohatsu, Yamaha Enduro) are usually of a simpler daydvut design but are more susceptible to vibrations, which requires paint elasticity.
Which paint is best used for DW?
For a daydwoot that is in constant contact with water and abrasives, two-component epoxy-polyurethane enamels are best suited. They are highly hard and chemically resistant. The usual alkyd enamels on the daydwoot wear off quickly and lose their appearance.