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Water Pump Impeller Kit – Fits Tohatsu/Nissan 40/50 HP 2-Stroke TLDI & 4-Stroke Outboards (Replaces 3T5-87322-3, 46-8M0046094)

Sale price $49.99 Regular price $79.00
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Water Pump Impeller Kit – Fits Tohatsu/Nissan 40/50 HP 2-Stroke TLDI & 4-Stroke Outboards (Replaces 3T5-87322-3, 46-8M0046094) is backordered and will ship as soon as it is back in stock.


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 aftermarket Water Pump Impeller Kit is designed for Tohatsu and Nissan 40–50 HP outboard motors, including 2-Stroke TLDI and 4-Stroke models manufactured between 2010 and 2014, plus select 2006 models. It provides all necessary components for a complete water pump service to restore engine cooling performance.

This kit serves as a direct replacement for Tohatsu/Nissan part numbers 3T5-87322-3, 3T5-87322-2, 3T5-87322-1, 3T5-87322-0 (and their -M suffixes), and Mercury/Mariner part 46-8M0046094.

  • Direct replacement components for a straightforward installation.
  • Includes a durable neoprene impeller and PA66 nylon housing for longevity.
  • Restores cooling system to factory specifications.

Part Number Matrix

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

Brand Part Number
Tohatsu / Nissan 3T5-87322-3, 3T5-87322-3M, 3T5-87322-2, 3T5-87322-2M, 3T5-87322-1, 3T5-87322-1M, 3T5-87322-0, 3T5-87322-0M
Mercury / Mariner 46-8M0046094

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Tohatsu MD40B2 40 2-Stroke TLDI 2010–2014 3T5-87322-3
Tohatsu MD50B2 50 2-Stroke TLDI 2010–2014 3T5-87322-3
Tohatsu MFS40A 40 4-Stroke 2014 3T5-87322-3
Tohatsu MFS50A 50 4-Stroke 2014 3T5-87322-3
Tohatsu MD40B(AQ) 40 2-Stroke TLDI 2006 3T5-87322-3
Tohatsu MD50B(AQ) 50 2-Stroke TLDI 2006 3T5-87322-3
Nissan NSD40B2 40 2-Stroke TLDI 2010–2014 3T5-87322-3
Nissan NSD50B2 50 2-Stroke TLDI 2010–2014 3T5-87322-3
Nissan NSF40A 40 4-Stroke 2014 3T5-87322-3
Nissan NSF50A 50 4-Stroke 2014 3T5-87322-3
Nissan NSD40B(AQ) 40 2-Stroke TLDI 2006 3T5-87322-3
Nissan NSD50B(AQ) 50 2-Stroke TLDI 2006 3T5-87322-3

Technical Specs

Product Type
Water Pump Impeller Service Kit
Installation
Direct replacement
Housing Material
Nylon PA66 Plastic
Housing Color
Black
Impeller Material
Neoprene Rubber
Warranty
1 Year

What’s in the Box

  • 1 x Water pump impeller (3C8-65021-2)
  • 1 x Impeller key (332-65022-0)
  • 1 x Pump case liner/Insert (3T5-65011-0)
  • 1 x Water pump guide plate (3C8-65025-0)
  • 1 x Guide plate gasket (3C8-65029-0)
  • 1 x Pump case gasket (3C8-65018-0 / 3T5-65018-2)
  • 4 x Screw/Bolt (910113-5855 / 9101E3-5855)

Installation Notes

  1. Disconnect the battery and shift linkage.
  2. Remove the lower unit mounting bolts and carefully lower the gearcase.
  3. Unbolt and remove the old water pump housing assembly.
  4. Clean the mounting surfaces and inspect the driveshaft for wear.
  5. Install the new impeller key, impeller, gaskets, plates, and liner from the kit.
  6. Secure the new water pump housing with the provided bolts, tightening to manufacturer torque specs.
  7. Reinstall the lower unit, ensuring the water tube and driveshaft are aligned.
  8. Reconnect the shift linkage and battery.
  9. Run the engine with a water supply and verify proper water outflow from the tell-tale port.

Troubleshooting & FAQ

How do I know if this kit fits my specific Tohatsu/Nissan engine?

This kit is designed for 40-50 HP Tohatsu and Nissan outboards, primarily 2-Stroke TLDI and 4-Stroke models from 2010–2014. We recommend cross-referencing your engine's model number and original part number with the compatibility tables on this page.

My engine is a 2006 model. Will this kit fit?

The kit is listed as compatible with select 2006 models, specifically the MD40B(AQ), MD50B(AQ), NSD40B(AQ), and NSD50B(AQ). Please verify your serial number and existing part to ensure a match.

What are the signs of a failing water pump impeller?

Common signs include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and reduced engine performance. It's recommended to replace the impeller as part of regular maintenance, typically every 1-2 years or 100-200 hours of use.

The kit lists different part numbers for the gasket and bolts. Which should I use?

These represent part number variations or supersessions from the manufacturer. Both versions included or referenced in the kit are designed to fit the compatible models listed. Use the components that match your existing hardware.

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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