Sierra 18-3429 Water Pump Repair Kit, Replaces Yamaha 6H4-W0078-00-00, Without Housing

The Sierra 18-3429 Water Pump Repair Kit is a complete rebuild kit for Yamaha outboard water pumps, supplied without the pump housing. It is designed to restore cooling system performance on outboards that use a matching water pump housing already in service, giving boat owners an economical way to renew wear components rather than replace the entire pump assembly. This kit is the same build as the Sierra 18-3408 kit, but 18-3429 omits the housing for applications where the original housing is still serviceable.

The kit bundles the wear items that fail most often in a water pump: bolts, a gasket, wear plates, an impeller, and an insert cup, so the full wear path of the pump can be renewed in one job. The color of the kit components is white. Each Sierra part is built to meet or exceed the specification of the original equipment part it replaces, and the kit cross-references directly to Yamaha OEM water pump repair kit part numbers, making it a straightforward drop-in replacement for outboards that call for those Yamaha kits.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3429
• Product Type: Water Pump Kit
• Housing Included: Without Housing
• Color: White
• Weight: 0.52 pounds
• Item Dimensions (L x W x H): 5 x 4.5 x 2.75 inches
• UPC: 030999975768
• OEM Cross Reference: 6H4-W0078-00-00, 6H4-W0078-A0-00
• Kit Contents: Bolt 18-0256 (qty 2), Bolt 18-0258 (qty 2), Gasket 18-0292, Wear Plate 18-0294, Impeller 18-3068, Insert Cup 18-3435, Wear Plate 18-3436

Fitment

Fits Yamaha outboard water pumps that use the 6H4-W0078-00-00 / 6H4-W0078-A0-00 repair kit.

Replaces (OEM)

• 6H4-W0078-00-00
• 6H4-W0078-A0-00

Frequently Asked Questions

What does the Sierra 18-3429 water pump kit include? The kit contains 2 bolts (18-0256), 2 more bolts (18-0258), a gasket (18-0292), two wear plates (18-0294 and 18-3436), an impeller (18-3068), and an insert cup (18-3435), covering the wear parts of a Yamaha outboard water pump rebuild.

Does the 18-3429 kit come with a pump housing? No, the Sierra 18-3429 kit is supplied without the pump housing. It is intended for rebuilds where the existing housing is still in good condition.

What OEM Yamaha part numbers does the 18-3429 kit replace? The 18-3429 kit replaces Yamaha part numbers 6H4-W0078-00-00 and 6H4-W0078-A0-00.

What is the difference between Sierra 18-3429 and Sierra 18-3408? Sierra 18-3429 and 18-3408 use the same kit components, but 18-3429 is sold without the pump housing while 18-3408 includes it.

How much does the 18-3429 water pump kit weigh? The Sierra 18-3429 water pump repair kit weighs 0.52 pounds.

What are the dimensions of the 18-3429 kit packaging? The kit measures 5 x 4.5 x 2.75 inches (length x width x height).

Is the Sierra 18-3429 kit a genuine OEM part or an aftermarket replacement? It is an aftermarket Sierra part manufactured to meet or exceed the specification of the original Yamaha equipment it replaces.

What color are the components in the 18-3429 kit? The components in the Sierra 18-3429 water pump kit are white.

How many bolts come in the 18-3429 kit and what sizes? The kit includes two 18-0256 bolts and two 18-0258 bolts, four bolts in total.

What is the UPC for the Sierra 18-3429 water pump kit? The UPC for the Sierra 18-3429 water pump kit is 030999975768.

Will the 18-3429 kit work if my outboard's pump housing is worn or cracked? No, because the 18-3429 kit does not include a housing, so it should only be used when the existing pump housing is still serviceable; a damaged housing requires a kit that includes one, such as the 18-3408.