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Water Pump Impeller – Fits Mercury Mariner & Yamaha 20-30 HP (Replaces 47-84797M, 689-44352-02)

Regular price $17.00

Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller – Fits Mercury Mariner 20-30 HP & Yamaha 25-30 HP (Replaces 47-84797M, 689-44352-02) is a crucial component for maintaining your engine's cooling system. It is designed for specific Mercury/Mariner 20–30 HP 2-Stroke engines (1984–1997) and Yamaha 25–30 HP 2-Stroke engines (1984–1997), ensuring reliable performance and fitment.

This part serves as a direct interchange for Mercury/Mariner part numbers 47-84797M/47-97793M; Yamaha 689-44352-02/689-44352-03/689-44352-00-00; Sierra 18-3067; CEF 500326; and Mallory 9-45600.

  • Engineered as a direct replacement part for straightforward installation.
  • Constructed with a durable plastic hub and robust neoprene blades.
  • Package includes one water pump impeller.

Part Number Matrix

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

Brand Part Number
Mercury/Mariner 47-84797M
Mercury/Mariner 47-97793M
Yamaha 689-44352-02
Yamaha 689-44352-03
Yamaha 689-44352-00-00
Sierra 18-3067
CEF 500326
Mallory 9-45600

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This impeller fits select Mercury and Mariner 2-stroke outboard models from 20 to 30 HP. Please verify your model code or exhaust type as noted.

Brand Model Rated HP Stroke OEM Part No. Notes
Mercury/Mariner 20C (Mode Code 6A9) 20 2-Stroke 47-84797M
Mercury/Mariner 25C (through propeller exhaust) 25 2-Stroke 47-84797M
Mercury/Mariner 25D 25 2-Stroke 47-84797M
Mercury/Mariner 28 HP (Mode Code 664) 28 2-Stroke 47-84797M
Mercury/Mariner 30A W30 (W-MARATHON) 30 2-Stroke 47-84797M

Fits various Yamaha 2-stroke outboards from 25 to 30 HP manufactured between 1984 and 1997, including C and CV series.

Brand Model Rated HP Stroke Years OEM Part No.
Yamaha 25 HP 25 2-Stroke 1984–1987 689-44352-02
Yamaha 30 HP 30 2-Stroke 1984–1987 689-44352-02
Yamaha CV25 25 2-Stroke 1989–1990 689-44352-02
Yamaha CV30 30 2-Stroke 1989–1990 689-44352-02
Yamaha C25 25 2-Stroke 1991–1997 689-44352-02
Yamaha C30 30 2-Stroke 1991–1997 689-44352-02

Technical Specs

Product Type
Water Pump Impeller
Installation
Direct replacement
Housing Material
Plastic hub with neoprene blades
Dimensions
Outer Diameter: 68.52 mm (2.7 in)
Height: 13.02 mm (0.51 in)
Internal Shaft Insert Diameter: 16.03 mm (0.63 in)
Weight
19 g (0.67 oz)
Blade Count
6

What’s in the Box

  • 1 × Water Pump Impeller

Installation Notes

  1. Disconnect the battery and ignition system for safety.
  2. Position the outboard vertically and drain the lower unit gear oil.
  3. Remove the mounting bolts securing the lower unit (gearcase) to the upper leg.
  4. Carefully lower the gearcase to expose the driveshaft and water pump assembly.
  5. Unbolt and remove the water pump housing cover.
  6. Slide the old impeller off the driveshaft, noting the original orientation of the blades.
  7. Clean the housing and wear plate surfaces, inspecting for grooves or damage.
  8. Lightly lubricate the new impeller and housing interior with a marine-safe soap or grease.
  9. Slide the new impeller onto the driveshaft while turning the shaft clockwise to set the blades correctly.
  10. Reinstall the water pump housing, ensuring all seals and gaskets are properly seated.
  11. Reassemble the lower unit to the engine, aligning the driveshaft and shift shaft.
  12. Refill the gearcase with fresh oil and reconnect the battery before testing.

Troubleshooting & FAQ

How do I know if my impeller needs replacing?

Common signs of a failing impeller include a weak or non-existent water stream from the "telltale" outlet, engine overheating alerts, or visible damage like cracked, brittle, or missing blades upon inspection.

How often should I replace my impeller?

As a preventative maintenance best practice, most manufacturers recommend replacing the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Usage in saltwater or sandy/silty conditions may require more frequent changes.

Will this fit my specific engine model?

This impeller is designed for the specific models and years listed in the compatibility tables. Always double-check your engine's model number and original part number against our lists. Do not purchase if your model is not explicitly listed.

What is the difference between this impeller and the OEM part?

This is an aftermarket part designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function. It offers a cost-effective solution without compromising on the quality of materials, using a durable plastic hub and neoprene blades suitable for marine environments.

Is the impeller hub plastic or metal?

This impeller features a durable, corrosion-resistant plastic hub, as specified in the technical details. This is a common and effective design for this engine class.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

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.

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