Mercury Outboard— How to Prevent Saltwater Corrosion

For boat owners, thinking about how to prevent saltwater corrosion, an issue that can cause significant damage, is a persistent thought. Thankfully, this enemy is not invincible. With anti-corrosion sprays, you can effectively safeguard your prized outboard. This article will guide you on how to protect your Mercury outboard from corrosive salt damage.

Understanding Saltwater Corrosion: The Silent Enemy

Salt-induced corrosion is a prevalent problem in marine equipment, particularly outboard motors. This silent enemy results from a chemical reaction between saltwater and the metal components of your boat’s motor. Understanding it is the first step toward effective prevention.

• What is corrosion? Corrosion is a natural process that converts refined metal into a more chemically stable form, such as oxide, hydroxide, or sulfide. In simpler terms, the process causes your metal to deteriorate over time.
• How does saltwater cause corrosion? Saltwater accelerates the corrosion process due to the presence of salts, which are excellent conductors of electricity. The heightened conductivity increases the rate of metal degradation, leading to quicker wear and tear of your outboard motor.
• The impact of salt-induced corrosion: Over time, salt-induced corrosion can lead to significant damage, such as engine failure, diminished motor efficiency, and a shortened lifespan of your outboard motor.
• Why tackle salt-induced corrosion? Taking action against corrosion caused by saltwater is crucial to ensure the longevity of your outboard motor, maintain its performance, and keep the costs of repair and replacement at bay.

Remember, knowledge is power. Understanding salt-induced corrosion makes you better equipped to protect your outboard motor against this pervasive threat.

How Often to Apply Anti-Corrosion Spray

Defining the optimal application frequency of anti-corrosion spray is key to maximizing its protective benefits. The frequency largely depends on the usage of your outboard motor and the conditions it’s exposed to. Here are a few general guidelines:

• Regular Usage in Saltwater: If your outboard motor is used frequently in saltwater, it’s advisable to apply anti-corrosion spray after every use. This regular application helps to counteract the consistent exposure to corrosive saltwater.
• Occasional Usage in Saltwater: Applying anti-corrosion spray once every 1-2 weeks should suffice for less frequent use in saltwater. Adjust this based on the actual usage and environmental conditions.
• Usage in Freshwater: If your outboard motor is primarily used in freshwater, the frequency of application can be lessened. In such cases, a monthly application may be sufficient.
• Off-Season Storage: Before storing your outboard for a significant period, thoroughly apply anti-corrosion spray to prevent any residual salt from causing damage during storage.

Remember, these are guidelines and not hard-and-fast rules. Monitor the condition of your outboard regularly and adjust the frequency of anti-corrosion spray application as needed to prevent saltwater corrosion.

What You’ll Need for the Job

Before starting the process of applying the anti-corrosion spray to your outboard motor, ensure you have all the necessary supplies at hand. In the video embedded below, Frank uses an anti-corrosion spray he buys in bulk commercial packaging. We’ve recommended consumer-packaged product. Here’s what you’ll need: 

4. Mercury Corrosion Guard
5. Gloves
6. Dry Cloth or Paper Towels

Step-by-Step: Applying Mercury Corrosion Guard Spray Effectively

The successful application of anti-corrosion spray involves a few critical steps to ensure maximum protection for your outboard motor. Here is a step-by-step guide:

1. Prepare the Outboard Motor: Start by ensuring that your outboard motor is level for effective application of the anti-corrosion spray. You may need to trim the motor down to achieve a level position.
2. Remove the Motor Cowling: The cowling or the outboard motor cover must be removed to ensure the anti-corrosion spray reaches all necessary components. Keep track of any screws or parts removed during this process to ensure easy reassembly.
3. Liberally Apply the Spray: With the can a few inches away from the surface, spray liberally over all the metal parts of the outboard motor. Be sure to cover all areas, but avoid spraying on the belt.
4. Reassemble the Motor: Reassemble the motor by replacing the cowling and any other removed components.

Following this comprehensive guide, you can effectively apply anti-corrosion spray, providing robust protection to your outboard motor against salt-induced corrosion.

Other Critical Steps to Prevent Saltwater Corrosion

Regular rinsing is also an essential part of protecting boats exposed to saltwater. Salt accumulates over time, so regular rinsing makes the job easier and more effective. In addition to rinsing the boat, owners should pay special attention to hard-to-reach areas like small crevices that are tricky and warrant detailed cleaning to prevent build-up and corrosion.

Products like Salt Off are specially formulated to remove salt and prevent corrosion. In addition to cleaning, Salt Off application also leaves boats with a protective coating that helps to prevent future decay.

Click here to read more about effective rinsing to further reduce the risks of saltwater corrosion.

Safeguarding Your Outboard: The Final Word

Salt-induced corrosion seriously threatens the health and longevity of any Mercury outboard motor. However, the right tools and knowledge can effectively manage this persistent foe. Applying an anti-corrosion spray using the steps provided in this guide can significantly extend the life of your outboard motor. In addition, leverage the power of quality salt removers like Salt Off.

Remember, prevention is always better than cure. A small investment in routine maintenance can save you from significant repair costs in the future. Rest easy— your outboard motor will resist the relentless challenge of salt-induced corrosion.

**Important Note**

Always consult your engine’s owner’s manual for instructions and information specific to your engine. If you need clarification on protecting your outboard from salt-induced corrosion, consult a Mercury Marine-certified mechanic.

PartsVu and Platinum Mobile Marine Partnership

Huge thanks go to Frank Cutri, the owner and operator of Platinum Mobile Marine, a mobile mechanic service serving the Lee County, Florida area, for partnering with PartsVu on the Boat Maintenance Matters series.

Together, we are working hard to build a library of step-by-step instructions on common outboard motor repair and maintenance tasks.