Mercury 115 HP Water Pump Impeller Replacement

Tools Needed

• Socket wrench and appropriate sockets for lower unit bolts
• Rubber mallet
• Vise or sturdy work surface
• Nylon brush
• Blue Loctite 242 thread locker
• Grease

Safety

• Wear gloves to protect hands from sharp edges and chemicals
• Be cautious when handling heavy parts to prevent injury

Steps

1. Put the lower unit in forward gear for easier removal.
2. Remove the five bolts securing the lower unit, using heat and penetrating oil if necessary.
3. Gently tap the lower unit with a rubber mallet to break any corrosion or seized threads.
4. Carefully remove the lower unit, ensuring not to scratch the skag on the vise or work surface.
5. Remove the water pump housing bolts, cleaning them as you go.
6. Inspect the impeller and replace if necessary.
7. Clean the drive shaft area to remove any corrosion or debris.
8. Install the new impeller, ensuring it's facing the correct direction.
9. Reassemble the water pump housing, using grease on the threads and bolts.
10. Apply thread locker to the lower unit bolts before reinstalling them.
11. Reattach the adapter for your shifter.
12. Test the lower unit by rotating the prop shaft and drive shaft.

Tips

• Use a board in the vise to protect the lower unit from scratches.
• Clean the threads on the bolts with a nylon brush before applying thread locker.
• Put the lower unit in forward gear before removal to make reinstallation easier.