Water Pump Impeller Kit – Fits Mercury/Tohatsu/Nissan 25-30 HP 4-Stroke (Replaces 853792A07)

$45.99 $73.00

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Water Pump Impeller Kit – Fits Mercury/Tohatsu/Nissan 25-30 HP 4-Stroke (Replaces 853792A07) 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 comprehensive Water Pump Impeller Kit – Fits Mercury/Tohatsu/Nissan 25-30 HP 4-Stroke (Replaces 853792A07) is designed for select Mercury, Tohatsu, and Nissan 25-30 HP 4-stroke outboard motors. It provides a reliable solution for maintaining your engine's cooling system, specifically fitting Mercury Marine models from serial number 0R051710 and up (including EFI) and a wide range of Tohatsu/Nissan 25-30 HP 4-stroke models.

This kit serves as a direct replacement for multiple OEM part numbers, including Mercury 853792A07, 853792A1, 853792T01, and Tohatsu/Nissan 361873220, ensuring a precise fit and function.

Engineered for direct replacement and easy installation.
Restores cooling system circulation to prevent overheating.
Includes all essential components: impeller, gaskets, and hardware.

Part Number Matrix

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

Brand	Part Number	Notes
Mercury	853792A07	Primary Replacement
Mercury	853792A1	Superseded Part
Mercury	853792T01	Superseded Part
Tohatsu / Nissan	361873220	Primary Replacement

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury Marine outboards, verify that your engine's serial number falls within the specified range (e.g., "0R106999 and above").

For Tohatsu and Nissan outboards, match your model number and manufacturing years from the list.

Brand	Model	Rated HP	Stroke	Years / S/N	OEM Part No.	Notes
Mercury	25 HP EFI	25	4-Stroke	0R106999 and above	853792A07	Gear Housing
Mercury	25 HP EFI JET	25	4-Stroke	0R165086 and above	853792A07	Gear Housing
Mercury	25 HP Sea Pro	25	4-Stroke	0R051710 and above	853792A07	Gear Housing (Driveshaft)
Mercury	30 HP EFI	30	4-Stroke	0R106999 and above	853792A07	Gear Housing

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Tohatsu	M25C3	25	4-Stroke	2002–2005	361873220
Tohatsu	M30A4	30	4-Stroke	2002–2003	361873220
Nissan	NS25C3	25	4-Stroke	2002–2005	361873220
Nissan	NS30A4	30	4-Stroke	2002–2003	361873220

Technical Specs

Product Type: Water Pump Impeller Repair Kit
Installation: Direct replacement
Primary Function: For outboard cooling system circulation

What’s in the Box

1 x Water Pump Impeller
4 x Mounting Bolts
1 x Metal Gasket with holes
1 x Dark Grey Gasket
1 x Metal Retainer with slot

Installation Notes

Disconnect the battery and ensure the engine is off and cool.
Drain the lower unit gear lube.
Remove the propeller and lower unit (gearcase) bolts.
Carefully detach the lower unit from the driveshaft housing.
Unbolt and remove the old water pump housing.
Remove the old impeller, gaskets, and key.
Clean all mating surfaces thoroughly, removing any old gasket residue.
Install the new gaskets, plate, and impeller from the kit. Ensure the impeller key is correctly seated.
Lubricate the inside of the housing and reinstall it, torquing bolts to manufacturer specifications.
Reattach the lower unit, ensuring the driveshaft, shift shaft, and water tube are aligned.
Refill the gear lube and test the engine cooling system using a flush-muff on land.

Troubleshooting & FAQ

How can I tell if this kit fits my specific Mercury outboard?

The most reliable method is to check your engine's serial number. This kit is compatible with Mercury 25-30 HP 4-stroke models with a serial number of 0R051710 and higher. You can find the serial number on a tag on the engine's transom bracket.

What are the signs of a failing water pump impeller?

Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and in some cases, a rattling or grinding noise from the lower unit. It is recommended to replace the impeller as part of regular maintenance, typically every 1-2 years or 100-200 hours of use.

Is this a complete kit for the job?

Yes, this kit includes the core components needed for a standard water pump service: the impeller, gaskets, plate, and new mounting bolts. You will only need standard mechanic's tools and a new supply of gear lube.

My Tohatsu engine isn't listed, will it fit?

This kit is specifically designed for the Tohatsu models M25C3 (2002–2005) and M30A4 (2002–2003). If your model or year is not listed, we cannot guarantee compatibility. Please cross-reference your OEM part number (361873220) to be certain.

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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