Yanmar 3GM30 Water Pump Impeller Replacement

Yanmar GM30F Impeller Replacement Guide

Tools Needed

• Socket wrench with 12mm and 7mm sockets
• Screwdriver (flathead)
• Needle-nose pliers
• Lubricant (included in replacement kit)

Safety

• Always close the seaock valve before starting any work on the raw water pump.
• Be cautious of galvanic corrosion when working with dissimilar metals.

Steps

1. Loosen and remove the hose clamp connected to the raw water pump.
2. Loosen and remove the 12mm bolts securing the pump to the engine, using a socket wrench.
3. Remove the two 7mm bolts securing the pump cover, using a screwdriver.
4. Disconnect the hoses from the pump and remove it from the engine.
5. Remove the old impeller and O-ring from the pump housing using needle-nose pliers.
6. Lubricate the new impeller and O-ring with the included lubricant.
7. Insert the new impeller into the pump housing, ensuring the part number is facing out (if applicable).
8. Place the new O-ring onto the pump housing.
9. Reassemble the pump cover using the stainless steel machine screws, applying TEF-Gel to prevent galvanic corrosion.
10. Reattach the hoses and secure them with the hose clamp.
11. Tighten all bolts to their original torque specifications.

Tips

• Ensure the impeller is turning when the pump wheel is turning by checking for a bar across the impeller.
• Inspect the heat exchanger cap regularly to prevent broken impeller blades from causing blockages and overheating.