Lower Unit Drain Plug Gasket – Fits Mercury, Mercruiser, Evinrude (Replaces 12-19183-3, 18-2244)

Lower Unit Drain Plug Gasket – Fits Mercury, Mercruiser, Evinrude (Replaces 12-19183-3, 18-2244)

This lower unit drain plug gasket provides a secure seal for gearcase drain and fill screws. It is compatible with a wide range of outboard and stern drive models, including most Mercury, Mercruiser, Evinrude, Johnson, and Tohatsu engines that utilize a 3/8-16 drain/fill screw.

It serves as a direct replacement for Mercury parts 12-19183, 12-19183-3, 12-19183K02, 12-19183Q02; Sierra 18-2244, 18-2945; SEI 98-102-09; Mallory 9-60101, 9-60102; and GLM 31170. Please note this gasket is not compatible with Japanese-origin Mercury/Mariner outboards.

• Essential Maintenance Part: These gaskets should be replaced with every lower unit oil change to prevent leaks.
• Secure Fit: Designed to install between the 3/8-16 drain/fill screw and the gearcase housing for a tight seal.
• Durable Material: Constructed from an oil-resistant blue plastic/nylon material to OEM specifications.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Confirm your engine model/year in the table below. For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson Serial Number Guide.

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

This product is available in the following package quantities:

• 10 x Lower Unit Drain Plug Seal Gaskets (Replaces 12-19183-3)
• 12 x Lower Unit Drain Plug Seal Gaskets (Replaces 12-19183-3)
• 15 x Lower Unit Drain Plug Seal Gaskets (Replaces 12-19183-3)
• 20 x Lower Unit Drain Plug Seal Gaskets (Replaces 12-19183-3)

Installation Guide

1. Place a suitable oil drain pan under the lower unit of your outboard or stern drive.
2. Using a large flathead screwdriver, locate and remove the lower drain/fill screw.
3. Remove the upper vent screw to allow air to enter, which helps the oil drain completely.
4. Inspect the old oil for any signs of water (milky appearance) or metal shavings.
5. Remove and discard the old gaskets from both the drain and vent screws.
6. Once draining is complete, install a new gasket onto the vent screw and reinstall it snugly.
7. Attach your gear lube pump to the lower drain hole and pump new lubricant in until it begins to flow out of the upper vent hole.
8. Install a new gasket on the drain/fill screw and quickly reinstall it to minimize oil loss.
9. Tighten both screws securely according to the manufacturer's specifications. Do not overtighten, as this can damage the gearcase.

Troubleshooting & FAQ

Q: How do I know if this gasket will fit my engine?
A: This gasket fits most Mercury/Mercruiser (25–400 HP), Evinrude/Johnson, and Tohatsu outboards that use a 3/8-16 drain/fill screw. It is a direct replacement for multiple part numbers like Mercury 12-19183-3. However, it does not fit Japanese-origin Mercury/Mariner models. Always check the part number cross-reference table and your engine's requirements.

Q: How often should I replace this drain plug gasket?
A: It is strongly recommended to replace this gasket every time you change your lower unit gearcase oil. Reusing an old gasket can lead to a poor seal and cause damaging water intrusion or oil leaks.

Q: What is this gasket made of?
A: This gasket is made from a high-quality, oil-resistant blue sealing material (plastic/nylon), designed to match OEM specifications for durability and a leak-proof seal under marine conditions.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.