Yamaha Water Pump Cartridge Gasket – Fits Yamaha & Mercruiser 40HP (Replaces 676-44324-A0, 676-44324-A1)
Yamaha Water Pump Cartridge Gasket – Fits Yamaha & Mercruiser 40HP (Replaces 676-44324-A0, 676-44324-A1) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
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
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Product Details
This is a replacement Yamaha Water Pump Cartridge Gasket designed for specific Yamaha 40HP 2-Stroke outboard motors (notably the 40Q series). It is also used in Mercruiser sterndrive applications that incorporate the equivalent Yamaha-sourced water pump assemblies.
It serves as a direct replacement for Yamaha part numbers 676-44324-A0, 676-44324-A1, and 676-44324-A1-00; Mercruiser 27-83399 and 83399M; and Sierra 18-99083.
- Installs in the lower unit water pump assembly.
- Functions as a seal between the water pump cartridge insert and the outer plate.
- Engineered from durable composite gasket material for a reliable seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 676-44324-A0 / 676-44324-A1 / 676-44324-A1-00 |
| Mercruiser | 27-83399 / 27-83399M / 83399 / 83399M |
| Sierra | 18-99083 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits specific Yamaha 40HP 2-Stroke outboards. Verify your engine's part diagram before ordering.
Used in Mercruiser sterndrives that utilize the corresponding Yamaha-sourced water pump assembly.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Yamaha | 40Q | 40 | 2-Stroke | 676-44324-A0, 676-44324-A1, 676-44324-A1-00 | Found in water pump assembly |
Technical Specs
- Product Type
- Water Pump Cartridge Gasket
- Installation Location
- Lower Unit Water Pump Assembly
- Material
- Gasket Material (Composition)
- Function
- Used between cartridge insert and outer plate in water pump assembly
- Product Dimensions
- 16.0 cm (L) x 10.0 cm (W) x 0.5 cm (H)
What’s in the Box
- 1 x Gasket, Cartridge (Replaces 676-44324-A0/A1)
Installation Notes
- Disconnect the negative battery terminal and remove the engine cowling.
- Place a drain pan under the lower unit and remove the gear lube drain/fill screws to drain the oil.
- Remove the bolts securing the lower unit (gearcase) to the engine's midsection and carefully lower it.
- Locate and unbolt the water pump housing cover.
- Remove the old cartridge gasket, noting its position. Thoroughly clean any old gasket residue from the mating surfaces of the housing and plate.
- Position the new cartridge gasket correctly.
- Reassemble the water pump housing components, ensuring all seals and parts are correctly aligned. Tighten bolts to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube align properly.
- Refill the gearcase with fresh marine gear lube until it flows from the upper vent hole.
- Reconnect the battery, start the engine using a water supply (flushing muffs), and verify a steady tell-tale stream, confirming correct pump operation.
Troubleshooting & FAQ
How do I know if this gasket fits my engine?
This gasket is for Yamaha 40HP 2-Stroke "40Q" series outboards and Mercruiser applications using the corresponding Yamaha water pump assembly. Always verify your required part number (e.g., 676-44324-A0, 27-83399M) against your engine's service manual or parts diagram before ordering.
What are the signs of a failed water pump gasket?
Common indicators include a weak or nonexistent "telltale" water stream, engine overheating alarms, or visible water leaks from the seam of the water pump housing. A damaged gasket compromises the pump's ability to create pressure.
Is this part sold separately or as part of a kit?
While this cartridge gasket is a standard component in complete water pump repair kits (like Yamaha p/n 6F5-W0078-A0-00), this listing is for the individual gasket only.
Can I reuse my old gasket after inspecting the water pump?
No. Gaskets are single-use components designed to crush and create a seal. Once the housing is disassembled, the old gasket should always be discarded and replaced to prevent leaks and ensure proper cooling performance.
Is there a difference between this and an OEM gasket?
Our aftermarket gasket is engineered to meet or exceed original equipment manufacturer (OEM) specifications for fit, material composition, and durability. It offers comparable performance and a reliable seal at a more accessible price.
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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
