Water Pump Service Kit for Mercury / Mariner Outboards (25HP–50HP)

High-quality aftermarket water pump service kit designed to match OEM performance.
Includes all the essential components required to restore proper cooling and water flow:

• Water pump impeller
• Upper gasket
• Lower gasket
• Woodruff key

Suitable for a wide range of Mercury and Mariner 2-stroke and 4-stroke outboards.
Ideal for routine service or impeller replacement.

Fitment – Mercury & Mariner Outboards

25 HP – 4 Stroke

• BigFoot / Command Thrust models only

30 HP & 40 HP – 4 Stroke (3-Cylinder, 3 Carburettors)

• Fits standard 3-carb 4-stroke models
• May also fit some earlier EFI 30HP & 40HP (serial number required to confirm)

30 HP & 40 HP – 2 Stroke (2-Cylinder, Single Carburettor)

50 HP – 4 Stroke (4-Cylinder, 4 Carburettors)

• Fits standard gearcase only
• Not compatible with BigFoot models

50 HP – 2 Stroke (3-Cylinder, 3 Carburettors)

• Fits late-model engines with CDM ignition coils
• Serial number check recommended if unsure

Not Compatible With

• Engines with serial numbers starting with 0N0…

If unsure, message us with your model and serial number and we will confirm the correct kit for your outboard.

Replaces Mercury OEM Part Numbers

Impeller

• 47-8508910
• 47-850893

Upper Gasket

• 27-822189

Lower Gasket

• 27-822217

Woodruff Key

• 28-85119
• 28-8M0032838

High-quality aftermarket replacements for the OEM part numbers listed above.

What’s Included

• Water pump impeller
• Upper gasket
• Lower gasket
• Woodruff key

Buyer Responsibility

Please check your engine model, year, gearcase type, and serial number before purchasing.
Mercury and Mariner engines in this HP range can use different water pump components, depending on production year and configuration.

If you’re unsure, message us — our technical team will help confirm the correct part for your engine.

For help choosing the right outboard parts, visit our guide:
https://ssimarine.co.uk/blogs/news/blogs-news-how-to-order-the-correct-outboard-parts

Return postage applies for items purchased in error or incorrect model selection.

25–50HP Water Pump Service Kit for Mercury & Mariner Outboards (2-Stroke & 4-Stroke)