Marine Mechanic how-to

How to Replace an Outboard Water Pump Impeller

Impellers fail and overheat engines.

Updated By the Career Education Institute Curriculum Team
Quick answer

Impellers fail and overheat engines. In short: drop; remove; pull, then complete the remaining steps below.

Step by step

  1. Drop the lower unit.

  2. Remove the pump housing.

  3. Pull the old impeller.

  4. Install the new impeller.

  5. Reassemble.

  6. Test water flow.

Safety reminders for marine mechanics

  • Ventilate before starting
  • Use fuel safely
  • Wear life jackets on trials
  • Lift engines safely

Outboard · Inboard · Sterndrive · Lower unit · Impeller · Trim: see the full marine mechanic glossary.

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