Has your Outboard Motor lost water pressure? Check your Impeller now!

How to Check for Wear and Damage in Your Yamaha Outboard Motors Water Pump

As a Yamaha outboard motor owner, maintaining your engine's health is crucial for optimal performance and longevity. One essential component to monitor is the water pump, responsible for cooling the engine and preventing overheating. Regular inspection of the water pump can help you determine if you need just an impeller replacement or a full water pump repair kit. Here’s a step-by-step guide to help you check for wear and damage in your Yamaha outboard motor water pump.

Preparation and Safety

Before you begin, ensure your outboard motor is off and cooled down. Gather the necessary tools, including screwdrivers, pliers, a socket set, and a service manual for your specific Yamaha model. Always wear safety gloves and glasses to protect yourself.

Removing the Lower Unit

Use the tilt mechanism to raise the motor, giving you better access to the lower unit.

Remove the Propeller, to ensures you have unobstructed access.

Using your socket set to remove, remove the bolts securing the lower unit to the upper unit.

Gently lower the unit, ensuring not to damage any components.

Accessing the Water Pump

Once the lower unit is removed, you will see the water pump housing located on top of the driveshaft.

Remove the water pump housing bolts using a socket wrench to remove the bolts.

Carefully lift the housing to expose the impeller and other components.

Inspecting the Impeller

The impeller is the heart of the water pump, responsible for moving water through the engine.

Check the blades, looking for any signs of wear, such as cracks, missing pieces, or uneven edges. If the blades are worn or damaged, the impeller needs replacing.

Check the Impellers keyway. The keyway should be intact and not worn down.

Inspecting the Water Pump Housing and Components

Check the inside of the housing for grooves, scratches, or warping. These can affect the pump's efficiency.

Inspect all gaskets and O-rings for cracks, tears, or compression. Damaged seals can lead to leaks and reduced performance.

Check the wear plate beneath the impeller for grooves or excessive wear. Any grove that can be detected by running your finger nail over it, is a sign of a damaged wear plate, and can affect water flow.

Determining the Necessary Repairs

If only the impeller blades or the hub are damaged, you may only need to replace the impeller. Remember that Impellers only have a one-year life span and should be replaced at one year or 100 hours of use.

If the housing, wear plate, gaskets, or O-rings show signs of wear or damage, it’s best to opt for a full water pump repair kit. This ensures all components are replaced, providing optimal performance and reliability.

Reassembling the Water Pump

If replacing parts, install the new impeller, gaskets, O-rings, and wear plate as necessary. Ensure the direction and placement of the parts is the same as when the items where removed.

Secure the water pump housing back onto the driveshaft.

Carefully lift and align the lower unit, securing it with the bolts you removed earlier.

Reinstall the propeller.

Testing the Repair

After reassembling, test your outboard motor in a water-filled test tank or on the water to ensure proper water flow and cooling.

Regularly inspecting your Yamaha outboard motor’s water pump is essential for maintaining engine performance and preventing costly repairs. By following these steps, you can determine whether you need a simple impeller replacement or a comprehensive water pump repair kit. Always refer to your service manual for specific instructions and part numbers for your Yamaha model.

Maintaining your water pump ensures your Yamaha outboard motor runs smoothly, keeping you safe and enjoying your time on the water.