One of the common problems with outboard motors is the formation of corrosion. I have owned and worked on a multitude of boats with outboards and took all necessary measures to avoid corrosion. In some cases, corrosion causes engine components to be doomed, especially the lower unit. Here is what you need to know about outboard motor corrosion repair and how to prevent it. 

Best Methods For Preventing Outboard Motor Corrosion

Without a doubt, the best measure of action is to prevent the onset of corrosion. There are a multitude of ways to reduce the likelihood that corrosion will begin to form. Here are the best actions to follow. 

Install, Monitor, And Replace Outboard Motor Zincs

Galvanic corrosion is serious business. To better understand galvanic corrosion, it is caused by two different types of metals coming in contact physically or electrically. Furthermore, the corrosion is exacerbated by seawater. The seawater is the medium that allows the flow of electrons between the two different metals. 

Unfortunately, the reactive metal will corrode, while the alternative metal will avoid becoming corroded. 

Fortunately, outboard motors are fitted with zincs. The zincs are the sacrificing metal, so to speak. Rather than the critical components of the motor becoming corroded, the zincs take the brunt of the work. 

With that said, it is imperative to monitor the condition of outboard zincs. In the event that they become excessively corroded, it is imperative to replace them in order to continue to protect the outboard motor metal. 

Flush The Outboard Motor After Use In Saltwater

As a captain, I have witnessed many boaters pull a boat out of saltwater and fail to flush the motor. Unfortunately, this is a significant reason why outboard motors become corroded, especially internally. 

Undoubtedly, an outboard motor that has been run in salt water must be flushed after each use. The flow of freshwater from a hose through a running motor will remove internal salt particulates. 

Salt that is left inside of the motor will cause internal corrosion. Never forget to flush an outboard motor. 

Outboard Motor Corrosion Repair

I’ll start out by saying that in some cases, severe outboard motor corrosion cannot be repaired. The damage can become too severe. 

Importantly, when minor corrosion of the outboard motor is spotted, it is important to take immediate action. Here is how to repair outboard motor corrosion. 

Be Safe While Repairing Outboard Motor Corrosion

Safety is of the utmost importance when it comes to treating outboard motor corrosion. With that said, I highly recommend the following before removing corrosion.

  • Put a pair of rubber gloves to protect your skin 
  • Disconnect the boat battery before performing any work
  • Place a blanket underneath the outboard to catch dust, dirt, and paint
  • Complete the work in a well-ventilated area, especially during the painting process
  • Take your time. Do not rush, or else you will not have the best possible outcome

Identify And Remove Corrosion

When corrosion is spotted on the outside housing of an outboard motor, it is important to prepare the area for treatment. 

I recommend thoroughly cleaning the motor to remove any oils or other contaminants. Once the motor is cleaned, use a wire brush and brush away the corrosion. 

After the corrosion is removed by brush, wash away the dust that formed before moving on to the next step. 

Protect The Surface Of The Outboard Motor

At this point, you’re ready to apply a protective coating over the area of corrosion. I recommend applying a zinc-chromate primer. This specific primer is ideal for marine environments to help reduce the onset of corrosion in the future. 

Once the primer has been applied and allowed to dry, it is time to add the top coat. Importantly, you’re going to want to purchase the correct paint that matches the current paint color on the motor. 

When applying the paint, make sure to cover the surface that was detailed completely with the wire brush. Importantly, you are likely going to need to add a second coat to the surface. Lastly, ensure that the paint has dried thoroughly before putting the boat back into the water. 

Prevent And Repair Outboard Motor Corrosion

Without question, the best alternative to repairing corrosion is preventing corrosion in the first place. You’ll want to take all preventative measures to avoid dealing with outboard corrosion. Not only will it cost money to repair, but it will put your boat out of service. Remember to replace depleted zinc, and follow the steps properly when it comes to repairing corrosion.