Foil Drive motors operate in a harsh marine environment and require regular cleaning and maintenance to keep them protected from corrosion.

If you notice surface corrosion, damaged paint, scratches or chips on your motor, the affected areas can often be cleaned and refinished before the corrosion becomes more significant.

This article explains how to clean, prepare and repaint the:

• External motor can / rotor
• Internal rotor and magnets
• Motor stator

Note: If you are not comfortable performing this maintenance yourself, contact your local Foil Drive Dealer or authorised repair centre, or contact Foil Drive Support to arrange servicing.

Before You Start

Regular inspection and maintenance can help prevent minor surface corrosion from developing into more serious damage.

If there is significant corrosion, pitting, material loss or damage to the magnets or motor components, do not simply repaint the affected area. The component may require replacement.

Replacement motor components are available through the Foil Drive repairs and spare parts range.

Instructional Videos

External Rotor Refurbishment 

Internal Rotor Refurbishment

Stator Refurbishment (Surface) 

Repairing Stator with Epoxy

Removing Bearings

Replacing & Securing Bearings

What You Will Need

• 120-grit and approximately 400-grit wet and dry sandpaper
• Isopropyl alcohol or suitable cleaning solvent
• Clean rags or paper towel
• Masking tape
• Good-quality black rust-preventative epoxy enamel spray paint suitable for metal surfaces
• 2.5 mm Foil Drive hex driver
• Replacement motor can protection sticker, if required
• Suitable lanolin-based corrosion inhibitor/lubricant for the rotor and stator

Only use paint and cleaning products that are suitable for the metal surfaces being treated. Follow the paint manufacturer's safety and application instructions, including ventilation and personal protective equipment.

Repainting the External Surface of the Rotor

The external surface of the rotor can be refinished if the paint has been damaged or light surface corrosion has started to form.

1. Remove the Propeller and Hub

Remove the propeller and hub from the motor.

The motor can remain attached to the mast, or the motor can be removed and secured safely on a suitable workbench.

2. Remove the Existing Sticker

Remove the old motor can protection sticker from the external surface of the rotor.

3. Remove Corrosion and Damaged Paint

Using wet and dry sandpaper, remove:

• Surface corrosion
• Loose or damaged paint
• Scratches or imperfections

Continue until the affected area is smooth and any corrosion has been removed.

For heavily affected areas, a coarser sandpaper can be used initially before finishing with a finer grit.

The objective is to remove the corrosion and leave a smooth, clean surface ready for painting.

4. Clean the Surface

Thoroughly clean the rotor using isopropyl alcohol or a suitable cleaning solvent.

Remove all sanding dust, grease, salt and other contaminants.

Allow the surface to dry completely before painting.

5. Apply Tape

Use masking tape to protect all areas that must not receive paint.

Pay particular attention to:

• Bearings
• Motor shaft

Do not allow paint to enter the motor bearings or onto the motor shaft.
 

6. Apply the Paint

Apply the epoxy enamel spray paint in very thin, light coats.

Allow each coat to dry according to the paint manufacturer's instructions before applying the next coat.

Multiple thin coats provide a more consistent finish and reduce the risk of paint runs or pooling.

7. Allow the Paint to Cure

Allow the paint to dry and cure completely before using the motor.

8. Install a New Motor Can Sticker

Once the paint is fully cured, install a new motor can protection sticker to provide additional protection to the external surface. 

Note: A spray adhesive can be applied to the sticker to improve retention.

Repainting the Internal Rotor and Magnets

The inside of the rotor contains the motor magnets and requires additional care.

1. Remove the Rotor

Remove the rotor from the stator and place it on a clean work surface.

2. Inspect the Magnets

Inspect the internal magnets carefully.

If there is:

• Minor paint loss
• Light surface corrosion
• No significant material loss

the rotor can generally be refurbished.

If there is significant corrosion, pitting or material loss from the magnets, the rotor may require replacement rather than refurbishment.

3. Remove Loose Corrosion and Paint

Use a small piece of sandpaper to carefully remove:

• Loose paint
• Surface corrosion
• Loose debris

Continue until the affected surfaces are clean and stable.

Wet and dry sandpaper can be used with water to help keep the abrasive surface clean during sanding.

4. Clean the Rotor

First wipe the internal surfaces with fresh water and a clean rag.

Then clean the surfaces thoroughly with isopropyl alcohol.

Allow the rotor to dry completely before painting.

5. Protect the External Surfaces

Apply tape to external surfaces of the rotor to prevent overspray, if needed.

6. Protect the Motor Shaft

The entire motor shaft must be protected from paint overspray.

Do not allow paint to build up on the motor shaft. Paint on the shaft can prevent it from passing through the ceramic bearings and may damage the bearings during reassembly.

A suitable tube or other protective covering can be used to shield the shaft during painting.

7. Apply the Paint

Apply the epoxy enamel using thin, light misting coats.

Do not apply heavy coats, as excess paint can run or pool inside the rotor.

Apply several light coats and ensure the internal surfaces receive consistent coverage.

8. Allow the Paint to Cure

Allow the paint to fully dry and cure before reassembly.

Follow the paint manufacturer's recommended curing time. As a minimum, allow sufficient time for the coating to fully harden before installing the rotor.

Do not rush reassembly. Paint that is not fully cured can be damaged during installation.

Repainting the Stator

The stator can also be cleaned and refinished if surface corrosion or paint damage is present.

1. Remove the Rotor

Remove the rotor from the stator and set it aside safely.

2. Clean the Stator

Clean the stator thoroughly using isopropyl alcohol.

3. Remove Surface Corrosion

Use wet and dry sandpaper to remove surface corrosion and smooth any damaged areas.

The stator does not need to be completely stripped back to bare metal. Remove the corrosion and ensure the surface is smooth and stable before painting.

4. Inspect the Copper Windings

Inspect the stator for any exposed copper wiring.

The copper windings have a protective coating, so visible copper does not necessarily indicate a problem.

If required, exposed areas can be protected using an appropriate marine-grade sealant.

For more information, see Repairing the Motor with Epoxy

5. Clean the Stator Again

After sanding, clean the stator again with isopropyl alcohol.

Ensure all sanding dust, salt, grease and other contaminants have been removed.

Allow the surface to dry completely.

6. Protect the Bearings

Carefully mask the ceramic bearings at both ends of the stator.

Also mask the aluminium base of the stator, which does not need to be painted.

7. Apply the Paint

Apply 3–4 very light coats of epoxy enamel.

Allow each coat to dry according to the paint manufacturer's instructions.

Avoid heavy coats that may run, pool or build up around the bearings.

8. Allow the Paint to Cure

Allow the paint to fully dry and cure before reinstalling the rotor.

Reassembly and Final Inspection

Before reassembling the motor:

1. Confirm all painted surfaces are completely dry and cured.
2. Remove all masking tape and protective coverings.
3. Check that no paint has entered the ceramic bearings.
4. Check that the motor shaft is completely free of paint.
5. Inspect the rotor and stator for any remaining corrosion or loose coating.
6. Reassemble the motor carefully.
7. Reinstall the hub and propeller.
8. Check that the propeller rotates smoothly and freely.
9. Apply the appropriate corrosion inhibitor/lubricant as part of your normal motor maintenance procedure.

If the rotor does not slide smoothly through the ceramic bearings, do not force it. Stop and inspect the shaft and bearings for paint contamination, corrosion or damage.

When Should the Motor Be Replaced?

Cleaning and repainting is suitable for minor surface corrosion and paint damage.

Contact Foil Drive Support if you find:

• Significant corrosion
• Deep pitting
• Significant material loss
• Damaged magnets
• Damaged bearings
• A damaged motor shaft
• Cracks or structural damage
• Any component that cannot be restored to a smooth, clean condition

In these cases, replacement components may be required.

Ongoing Motor Care

Regular maintenance will help protect your motor from the marine environment.

For more information on cleaning your system, click here.

After Riding

• Rinse the motor thoroughly with fresh water.
• Allow the motor to dry.
• Inspect for scratches, chips or early signs of corrosion.
• Address damaged paint or surface corrosion before it becomes more severe.
• Use an appropriate corrosion inhibitor/lubricant as recommended by Foil Drive.

Regular inspection and early maintenance can significantly reduce the chance of minor surface corrosion developing into more serious motor damage.