Water Pump Repair Kit – Fits Yamaha 20HP/25HP 2-Stroke Outboards (Replaces 6L2-W0078-00-00)

Product Details

This Water Pump Repair Kit – Fits Yamaha 20HP/25HP 2-Stroke Outboards (Replaces 6L2-W0078-00-00) is designed to restore cooling system performance on select Yamaha 2-stroke outboards. It is specifically engineered for two-cylinder 20HP models from 1996–1997 and 25HP models from 1988–2009.

The kit serves as a direct replacement for Yamaha OEM part 6L2-W0078-00-00 and interchanges with Sierra 18-3431, SouthMarine 6L2-W0078-00, MARKGOO 6L2-W0078-00-00, SLSRPMT 6L2-W0078-00-00, and ZDCBMDB 6L2-W0078-01/6L2-W0078-00.

• Installs as a direct OEM-equivalent replacement.
• Features a durable neoprene impeller for reliable water flow.
• Includes essential hardware for a complete service.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This kit is compatible with a wide range of Yamaha two-cylinder, 2-stroke outboards rated at 20HP and 25HP.

Technical Specs

Product Type

Water Pump Repair Kit

Installation

Direct OEM replacement

Fuel Type

Gasoline

Housing Material

Metal

Housing Color

Black

Dimensions

152.4 mm × 152.4 mm × 76.2 mm (6 × 6 × 3 inches)

Weight

0.18 kg (6.5 ounces)

Engine Type

2-Stroke

Engine Position

Outboard

Impeller Material

Neoprene

Impeller Blades

6

Impeller Height

18.95 mm

Impeller Diameter

51.99 mm

Shaft Diameter

13.65 mm

Warranty

30-day returns

What’s in the Box

• 1 x Outer Plate, Cartridge (6L2-44323-00-00)
• 1 x O-Ring (93210-45161-00)
• 1 x Impeller (6L2-44352-00-00)
• 1 x Insert, Cartridge (6L2-44322-00-00)
• 4 x Bolt with washer (97095-06040-00)
• 1 x Woodruff Key (90280-03024-00)

Installation Notes

1. Disconnect the battery and remove the engine cover.
2. Shift the outboard into neutral.
3. Unbolt and carefully lower the gearcase/lower unit from the driveshaft housing.
4. Remove the old water pump housing and its components, noting their orientation.
5. Clean the mounting surfaces and inspect for any damage or corrosion.
6. Install the new gasket, wear plate, impeller, and key from the kit. Ensure the impeller vanes are oriented correctly for your engine's rotation.
7. Lubricate the inside of the new housing and install it over the impeller.
8. Secure the new housing with the provided bolts, tightening them to the manufacturer's torque specification.
9. Grease the driveshaft splines and reinstall the lower unit, ensuring the water tube and shift shaft align correctly.
10. Reconnect the battery and test the engine with a water supply, checking for proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.