How to Run a Boat Motor Out of Water

Running a boat motor out of water is essential for maintenance tasks such as flushing the engine or testing its functionality. However, this must be done carefully to avoid damaging the engine. Follow these steps to safely and effectively run your boat motor while it’s out of the water.

Part 1: Attaching a Hose and Motor Flusher Muffs

1. Check Your Owner’s Manual

• Locate the water intake ports and confirm whether your motor has built-in hose attachments.
• Review the manufacturer’s guidelines for running the motor out of water.

2. Attach the Hose

• For built-in attachments: Screw the garden hose directly into the motor’s water intake port. Cover the other intake with tape if required.
• For motors without built-in attachments: Use motor flusher muffs.

3. Use Motor Flusher Muffs

• Wet the rubber ends of the muffs for a better seal.
• Position the muffs over the water intake ports on the motor’s lower unit, ensuring the connecting rod faces away from the propeller.
• Attach the garden hose to the muff nozzle and tighten securely.

Part 2: Starting the Engine

1. Turn On the Water

• Turn the faucet to supply water to the motor. Check the manual for recommended water pressure, typically set to about half.

2. Shift the Engine to Neutral

• Make sure the throttle or gearshift is in the neutral position to prevent accidental propeller movement.

3. Start the Motor

• Insert the key or pull the starter to turn on the engine. For electric motors, you may need to press an additional button after turning the key.

4. Check the Water Pump Flow

• Ensure a steady stream of water flows from the motor’s outflow or “pee hole.”
• If no water flows:
  • Turn off the engine immediately.
  • Use a thin wire to clear debris from the outflow tube.
  • Restart the engine to see if the problem is resolved. If not, the water pump impeller may need replacement.

Part 3: Flushing the Motor

1. Run the Engine for 5–10 Minutes

• Allow the engine to run for the recommended time, typically 5–10 minutes.
• Monitor the water flow and ensure the muffs stay securely in place.

2. Turn Off the Engine First

• Shut off the engine before turning off the water to prevent damage to the motor’s cooling system.

3. Disconnect the Hose

• Unscrew the garden hose from the motor or muffs and store it away.

4. Remove the Muffs

• If using muffs, slide them off the lower unit and store them for future use.

5. Drain Water from the Motor

• Leave the motor in the vertical position for 30–60 minutes to allow all water to drain.
• After draining, tilt the motor for storage.

Tips for Safe Operation

• Monitor Constantly: Never leave the motor unattended while it’s running out of water.
• Avoid Overheating: Running the motor without water for even a short time can cause significant damage.
• Inspect Regularly: Check the water pump and impeller periodically to ensure proper functioning.

Warnings

• Propeller Hazard: Ensure the engine is in neutral and stay clear of the propeller at all times.
• Avoid Prolonged Use: Running the engine out of water for more than 15 minutes can overheat the motor.

By following these steps, you can safely and effectively run your boat motor out of water for maintenance and flushing tasks.