10-Pack Lower Unit Drain Plug Seal Gaskets for Mercury/MerCruiser Outboard and Sterndrive Applications – Replaces 12-19183-3, 12-19183Q02 and 12-19183K02
10-Pack Lower Unit Drain Plug Seal Gaskets for Mercury/MerCruiser Outboard and Sterndrive Applications – Replaces 12-19183-3, 12-19183Q02 and 12-19183K02 is backordered and will ship as soon as it is back in stock.
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10-Pack Lower Unit Drain Plug Seal Gaskets for Mercury/MerCruiser O...
10-Pack Lower Unit Drain Plug Seal Gaskets for Mercury/MerCruiser Outboard and Sterndrive Applications – Replaces 12-19183-3, 12-19183Q02 and 12-19183K02 is backordered and will ship as soon as it is back in stock.
Product Details
This lower unit drain plug seal gasket is designed for Mercury and MerCruiser outboard and sterndrive gearcases that use a 3/8-16 drain or fill screw. It helps seal the drain, vent or oil-level plug opening during gear lubricant service and helps reduce the risk of gear oil leakage and water intrusion.
This aftermarket replacement is listed for use in applications associated with Mercury references 12-19183-3, 12-19183Q02 and 12-19183K02. Additional aftermarket reference numbers are provided below for cross-reference purposes. Always compare the existing gasket, plug and service information before ordering.
- Designed for single-use installation during a gear lube change.
- Oil-resistant sealing material for lower-unit service applications.
- Helps keep lubricant in and moisture out when correctly installed.
- Supplied as a 10-piece pack.
Part Number Matrix
The following numbers are reference listings associated with this gasket style. Confirm the exact application before purchase.
| Brand | Part Number |
|---|---|
| Mercury | 12-19183-3 |
| Mercury | 12-19183Q02 |
| Mercury | 12-19183K02 |
| Sierra | 18-2244 |
| Sierra | 18-2945 |
| SEI | 98-102-09 |
| Mallory | 9-60101 |
| Mallory | 9-60102 |
| GLM | 31170 |
| Red Rhino | MR-103 |
Engine and Model Compatibility
This gasket is intended for compatible Mercury, Mariner and MerCruiser applications using the specified 3/8-16 drain or fill screw. Model coverage varies by gearcase and production configuration, so verify the reference number and plug dimensions against the service manual or original gasket before installation.
| Brand | Application | Rated HP | Stroke | Years | Reference Part No. | Fitment Notes |
|---|---|---|---|---|---|---|
| Mercury | Compatible outboard gearcases | Multiple | 2-Stroke and 4-Stroke applications | Multiple | 12-19183-3 | For applications using the matching 3/8-16 drain or fill screw; verify the exact model and gearcase. |
| Mariner | Compatible outboard gearcases | Multiple | 2-Stroke and 4-Stroke applications | Multiple | 12-19183-3 | Confirm the part number and original gasket before ordering. |
| MerCruiser | Compatible sterndrive gearcases | Multiple | Not applicable | Multiple | 12-19183-3 | For compatible drain, vent or oil-level plug applications using the matching gasket. |
Do not assume fitment for Japan-made Mercury or Mariner models, or for any model with a different plug thread or gasket size. Consult the applicable service information when the origin, model year or gearcase configuration is uncertain.
Technical Specifications
- Product Type
- Lower unit drain plug seal gasket
- Pack Quantity
- 10 gaskets
- Installation
- Fits compatible 3/8-16 drain or fill screw applications
- Material
- Non-asbestos sealing material
- Color
- Black
- Dimensions
- Outside diameter: 14.2 mm (0.56 inch); inside diameter: 9 mm (0.35 inch)
- Thread Compatibility
- For 3/8-16 drain or fill screw applications
- Application
- Outboard and sterndrive gearcase drain, vent and oil-level plug service
- Function
- Helps seal the plug opening and reduce gear oil leakage and water intrusion
- Replacement Interval
- Single-use gasket; replace during each applicable gear oil service
What's in the Box
- 10 x Lower Unit Drain Plug Seal Gaskets
Installation Notes
- Place a suitable drain pan beneath the lower unit.
- Remove the lower magnetic drain plug and the old gasket. Inspect the magnet for abnormal metal debris.
- Remove the upper gearcase vent screw so air can enter while the lubricant drains.
- Allow the gear lubricant to drain completely.
- Clean the drain plug, vent plug and sealing surfaces.
- Install one new gasket on the applicable drain or fill plug. Do not reuse a compressed gasket.
- Fill the gearcase with the lubricant specified for your engine through the lower opening until lubricant reaches the upper vent opening.
- Reinstall the upper vent screw as specified by the service procedure, then install the lower plug with the new gasket. Tighten to the manufacturer's specified torque and do not overtighten.
Troubleshooting and FAQ
How do I know if this gasket will fit my engine?
Confirm that your application uses the matching reference number and a 3/8-16 drain or fill screw. Compare the original gasket's dimensions and consult the engine or sterndrive service manual, especially for Japan-made models or configurations with an unknown gearcase.
Can I reuse this gasket?
No. This is a single-use sealing gasket. Replace it after removal because a previously compressed gasket may not seal reliably during the next service.
What are the signs of a failing drain plug gasket?
Possible signs include lubricant weeping around the plug, a low gearcase lubricant level or water-contaminated lubricant that appears milky or creamy. Inspect the plugs, gaskets and other gearcase seals before returning the unit to service.
How does this aftermarket gasket compare with an OEM gasket?
This is an aftermarket replacement intended for compatible applications associated with the reference numbers listed above. It is not a Mercury or MerCruiser OEM component. Verify fitment and dimensions before installation.
Does the package include the drain plug?
No. The package contains ten replacement seal gaskets only. Drain and vent plugs are not included.
What should I do if the gasket still leaks?
Stop operation and inspect the plug, threads, sealing surface and gasket orientation. Confirm that the correct lubricant level and tightening procedure were used. A damaged plug, distorted sealing surface or incorrect gasket size may also cause leakage.
Safety and Important Information
- Verify the reference number, dimensions and plug thread against your original part or service manual before purchase.
- This is an aftermarket replacement, not an OEM component.
- Use the lubricant and tightening specifications recommended for your specific engine or sterndrive.
- Do not operate the unit if lubricant leakage or water contamination is present.
- Professional installation is recommended when the correct application or service procedure is uncertain.
About Sea Sierra
- Pro-Grade Standards — Marine replacement parts selected for dependable service applications.
- Global Fulfillment — Shipping options and delivery estimates are shown at checkout based on the destination.
- Manufacturer-Direct Value — Practical replacement parts at competitive prices.
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