Lower Unit Drain Screw Gasket – Fits Mercury/Mercruiser All HP (Replaces 12-19183-3, 12-19183K02, 12-19183Q02)
Lower Unit Drain Screw Gasket – Fits Mercury/Mercruiser All HP (Replaces 12-19183-3, 12-19183K02, 12-19183Q02) is backordered and will ship as soon as it is back in stock.
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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
Lower Unit Drain Screw Gasket – Fits Mercury/Mercruiser All HP (Rep...
Product Details
This Lower Unit Drain Screw Gasket is designed for a secure, leak-free seal on Mercury Marine outboard and MerCruiser stern drive engines. It fits all horsepower models that are equipped with standard 3/8-16 drain and fill screws, ensuring reliable performance and protection for your gearcase.
It serves as a direct replacement for multiple OEM and aftermarket parts, including Mercury Marine 12-19183-3, 12-19183K02, 12-19183Q02, and Sierra 18-2244.
- Installs on all standard 3/8-16 lower unit drain and fill screws.
- Engineered to provide a positive seal that prevents gear lube leakage.
- Package includes 12 gaskets, providing enough for multiple services.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury Marine | 12-19183-3 |
| Mercury Marine | 12-19183K02 |
| Mercury Marine | 12-19183Q02 |
| Sierra | 18-2244 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
These gaskets are confirmed to fit a wide range of Mercury outboards and MerCruiser stern drives, excluding certain Japanese-origin Mercury models.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercury | All outboard models with 3/8-16 drain/fill screws | All | 2-Stroke & 4-Stroke | 12-19183-3/12-19183K02/12-19183Q02 | Except Japanese-origin models |
| MerCruiser | All stern drive models | All | 4-Stroke | 12-19183-3/12-19183K02/12-19183Q02 |
Technical Specs
- Product Type
- Drain Screw Gasket
- Installation
- Used with 3/8-16 drain/fill screws
- Housing Material
- Plastic
- Housing Color
- Blue
- Thread Size
- For 3/8-16 screws
- Other Technical Attributes
- Provides tightness to prevent oil leakage
What’s in the Box
- 12 x Drain Screw Gasket (Replaces 12-19183-3, 12-19183K02, 12-19183Q02)
Installation Notes
- Position a suitable drain pan under the lower unit.
- Remove the lower drain/fill screw, followed by the upper vent screw to allow air entry.
- Allow the gear lube to drain completely. Inspect the old oil for any contaminants.
- Clean the drain plug and the area around the drain hole.
- Remove the old gasket from the drain screw and install a new one.
- Refill the lower unit with the manufacturer-specified gear lube through the bottom hole until it emerges from the upper vent hole.
- Reinstall the upper vent screw and its gasket first, then reinstall the lower drain screw with its new gasket.
- Tighten both screws securely to the manufacturer's specified torque. Do not overtighten.
Troubleshooting & FAQ
How do I know if this gasket will fit my engine?
This gasket is designed for Mercury and MerCruiser models using 3/8-16 drain/fill screws. It is not compatible with Japanese-origin Mercury models. Always check your OEM part number or screw size before ordering to ensure correct fitment.
What are the signs of a failing drain screw gasket?
The most common sign of a failing gasket is gear lube leaking from the drain screw. You might notice an oily sheen on the water around your lower unit or drips of oil on the ground when the boat is stored. A compromised seal can allow water to enter the gearcase, leading to severe damage.
How often should I replace my lower unit gaskets?
It is best practice to replace the drain and vent screw gaskets every time you change your lower unit gear lube. This is typically recommended at least once per season or every 100 hours of operation, whichever comes first.
Is there a difference in quality between these and OEM gaskets?
Our aftermarket gaskets are engineered to meet or exceed OEM specifications for material and performance. They provide a reliable seal at a more accessible price point.
What is the main cause of gasket failure?
Gaskets can fail due to age, repeated use (over-compression), or improper installation (over-tightening or under-tightening). Using a new gasket for each service is the best way to ensure a proper seal.
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
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