Water Pump Impeller Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 46-92970A5, 47-89980Q1)

$55.50 $88.00

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Water Pump Impeller Kit – Fits Mercury/Mariner 3.9-9.8 HP (Replaces 46-92970A5, 47-89980Q1) is backordered and will ship as soon as it is back in stock.

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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 Kit is a direct-fit replacement for Mercury and Mariner 2-stroke outboard engines ranging from 3.9 to 9.8 HP, manufactured between 1975 and 1986. It is specifically designed for models with a 0.438-inch driveshaft diameter, ensuring reliable cooling system performance.

It serves as a direct cross-reference for multiple OEM and aftermarket part numbers, including Mercury 46-92970A5, 47-89980T1, 47-89980Q1, Sierra 18-3446, GLM 89650, and CEF 500390.

Direct replacement installation requires no modifications.
Complete kit includes all necessary gaskets for a full water pump service.
Engineered for vintage outboards with a 0.438" shaft diameter.

Part Number Matrix

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

Brand	Part Number
Mercury	46-92970A5
Mercury	47-89980T1
Mercury	47-89980Q1
Sierra	18-3446
GLM	89650
CEF	500390

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mariner owners: This kit fits a specific range of vintage 2-stroke outboards from 1975–1986. Please verify your horsepower and shaft diameter (0.438") before ordering.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Outboard	3.9	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Mercury	Outboard	4	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Mercury	Outboard	4.5	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Mercury	Outboard	6	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Mercury	Outboard	7.5	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Mercury	Outboard	9.8	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter
Force	Outboard	3.9-9.8	2-Stroke	1975–1986	46-92970A5	0.438" shaft diameter

Technical Specs

Product Type: Water Pump Impeller Kit
Installation: Direct Replacement
Impeller Insert Size: 0.438 inch (11.13 mm)
Warranty: 1 Year
Kit Contents: Complete kit includes impeller and all necessary gaskets for water pump service.

What’s in the Box

Impeller
Gaskets
Seals

Installation Notes

Disconnect the spark plug leads and battery for safety.
Shift the outboard into neutral and remove the lower unit (gearcase) bolts.
Carefully lower and remove the gearcase, disconnecting the shift shaft if necessary.
Unbolt and remove the water pump housing cover to access the impeller.
Remove the old impeller, gaskets, and wear plate, noting their orientation.
Clean all mating surfaces thoroughly, removing any old gasket material or debris.
Install the new gaskets, wear plate, and impeller. Lightly grease the impeller and housing interior.
Turn the driveshaft clockwise while pressing down on the housing to correctly seat the impeller vanes.
Secure the housing cover with the bolts, tightening to the manufacturer's specified torque.
Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
Once reassembled, test the engine in a suitable water source to confirm water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?

Verify your engine is a Mercury, Mariner, or compatible Force 2-stroke model between 3.9 and 9.8 HP, manufactured from 1975 to 1986. The most critical dimension is the driveshaft diameter, which must be 0.438 inches.

What are the signs of a worn-out water pump impeller?

Common symptoms include the engine running hotter than normal, a weak or intermittent water stream from the tell-tale indicator, or visible damage like cracked, brittle, or missing vanes on the impeller itself upon inspection.

How often should I replace my impeller?

As a best practice for preventative maintenance, inspect your impeller annually and plan for replacement every 1-2 years or 100-200 hours of operation, especially if you frequently operate in saltwater or debris-heavy water.

Is everything needed for the job included?

Yes, this is a complete service kit. It includes the impeller along with all the required gaskets and seals for a standard water pump replacement.

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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