Sierra 18-3475 Water Pump Repair Kit Without Housing for Yamaha T9.9 (2007-17), Replaces 69G-W0078-00

The Sierra 18-3475 is a water pump repair kit built for the cooling system on Yamaha T9.9 outboards (2007-17). Supplied without a housing, this kit is designed for owners replacing worn internal wear components rather than the full pump body, making it a targeted fix when the housing itself is still in good condition. The kit replaces OEM number 69G-W0078-00 and is a direct match for the cooling system service parts on this application.

Inside the kit you get the two core wear items that typically fail first in a water pump: a cup insert (Sierra 18-3444, O.E. 63V-44322-00, quantity 1) and an impeller (Sierra 18-3040). The cup insert provides the wear surface the impeller vanes ride against, and replacing it alongside the impeller during a service interval helps the new impeller seal and perform correctly, since an old, worn cup insert can accelerate wear on a fresh impeller.

This repair kit is intended for routine cooling system maintenance and for restoring proper raw water flow after impeller wear, overheating, or a failed pump inspection. Because it ships without a housing, it is meant to pair with your existing water pump housing during a rebuild.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3475
• Product Type: Water Pump Repair Kit
• Housing Included: No (Without Housing)
• Kit Contents: Cup Insert (Sierra 18-3444, O.E. 63V-44322-00, Qty 1); Impeller (Sierra 18-3040)
• Replaces (OEM): 69G-W0078-00
• Fitment: Yamaha T9.9 (2007-17)
• Weight: 0.38 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 808282376833

Fitment

• Yamaha T9.9 (2007-17)

Replaces (OEM)

• 69G-W0078-00

Frequently Asked Questions

What does the Sierra 18-3475 water pump kit fit? The Sierra 18-3475 is designed for Yamaha T9.9 outboards (2007-17) cooling system service.

Does the 18-3475 kit include the water pump housing? No. The Sierra 18-3475 is a repair kit without housing, meaning it supplies the internal wear parts for reuse with your existing water pump housing rather than a complete new housing assembly.

What OEM part number does the Sierra 18-3475 replace? It replaces OEM number 69G-W0078-00, so it is a direct cross-reference for that Yamaha part.

What is included in the 18-3475 repair kit? The kit contains a cup insert (Sierra 18-3444, O.E. 63V-44322-00, quantity 1) and an impeller (Sierra 18-3040), the two wear components most commonly replaced during a water pump service.

How much does the 18-3475 kit weigh? The Sierra 18-3475 water pump repair kit weighs 0.38 pounds.

Why does the impeller need a new cup insert instead of just replacing the impeller alone? A worn cup insert provides a degraded wear surface for the impeller vanes, so replacing both parts together, as included in the 18-3475 kit, helps the new impeller seal and wear correctly from the start.

Is the cup insert in this kit an OEM part number? The cup insert included in the 18-3475 kit is Sierra part 18-3444, which corresponds to OEM number 63V-44322-00.

Will this kit work if my water pump housing is damaged? The 18-3475 kit does not include a housing, so if your existing housing is cracked or worn beyond spec, it will need to be replaced or repaired separately in addition to installing this kit.

What is the part number for the impeller in this kit? The impeller included in the Sierra 18-3475 kit is Sierra part 18-3040.

Is this a genuine Sierra part? Yes, this is a Sierra-branded water pump repair kit, part number 18-3475.

What are the dimensions of the 18-3475 kit packaging? The Sierra 18-3475 kit measures 0.39 x 0.39 x 0.39 inches.