Exhaust Outer Cover Gasket – Fits Yamaha/Mercury Marine 4HP-5HP Outboards (Replaces 6E0-41114-A1-00, 21-41279M)
Exhaust Outer Cover Gasket – Fits Yamaha/Mercury Marine 4HP-5HP Outboards (Replaces 6E0-41114-A1-00, 21-41279M) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Exhaust Outer Cover Gasket – Fits Yamaha/Mercury Marine 4HP-5HP Out...
Product Details
This Exhaust Outer Cover Gasket creates a crucial seal between the exhaust outer cover and the cylinder block. It is designed for a precise fit on Yamaha 4HP–5HP 2-Stroke outboards from 1984–1999 and compatible Mercury/Mariner 4HP–5HP 2-Stroke models from 1984–1990.
This part directly replaces Yamaha OEM part numbers 6E0-41114-01-00 and 6E0-41114-A1-00, as well as Mercury/Mariner interchange parts 21-41279M, 27-41279M, 27-99993M, 41279M, and 99993M.
- Installs externally on the cylinder block assembly.
- Engineered for use in marine saltwater and freshwater environments.
- Package includes one gasket for a complete single-part replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Mercury/Mariner | 21-41279M | |
| Mercury/Mariner | 27-41279M | |
| Mercury/Mariner | 27-99993M | |
| Mercury/Mariner | 41279M | |
| Mercury/Mariner | 99993M |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha Owners: This part is confirmed to fit the specific 4HP and 5HP models and years listed, covering series like 4AC, 4AS, 4A, and various letter-coded year models (e.g., 4LN, 4SK, 5LK).
For Mercury/Mariner Owners: This part fits a general range of 4HP and 5HP 2-stroke outboards manufactured between 1984 and 1990. Please verify by part number, as specific model data is not available.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 4AC (6E0) | 4 | 2-Stroke | 1985–1990 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4AS (6E1) | 4 | 2-Stroke | 1987–1990 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4A (6E2) | 4 | 2-Stroke | 1987 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LN, 4SN | 4 | 2-Stroke | 1984 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LK, 4SK | 4 | 2-Stroke | 1985 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LJ, 4SJ | 4 | 2-Stroke | 1986 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LH, 4SH | 4 | 2-Stroke | 1987 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LG, 4SG | 4 | 2-Stroke | 1988 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LF, 4SF | 4 | 2-Stroke | 1989 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4LD, 4SD | 4 | 2-Stroke | 1990 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4MLHP, 4MSHP | 4 | 2-Stroke | 1991 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4AC | 4 | 2-Stroke | 1993 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 4AS | 4 | 2-Stroke | 1993 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 5LN, 5SN | 5 | 2-Stroke | 1984 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Yamaha | 5LK, 5SK | 5 | 2-Stroke | 1985 | 6E0-41114-A1-00 | Supersedes 6E0-41114-01-00 |
| Mercury/Mariner | Various | 4 | 2-Stroke | 1984–1990 | 21-41279M |
Technical Specs
- Product Type
- Exhaust Outer Cover Gasket
- Installation
- External mounting between exhaust outer cover and cylinder block
- Dimensions
- 14.0cm x 13.5cm x 0.1cm
- Weight
- 4g (0.14 oz)
- Other Technical Attributes
- For use with outer exhaust cover assembly
What’s in the Box
- 1 x Gasket, Exhaust Outer Cover (Replaces 6E0-41114-A1-00)
Installation Notes
- Ensure the engine is off, cool, and disconnected from the power source.
- Locate and unbolt the exhaust outer cover from the cylinder block.
- Carefully remove the old gasket, taking note of its orientation.
- Thoroughly clean both mating surfaces. Scrape away any old gasket material or sealant, ensuring the surfaces are smooth and free of debris.
- Position the new gasket, aligning it with the bolt holes exactly as the original was placed.
- Re-install the exhaust outer cover.
- Tighten the bolts in a crisscross pattern to the manufacturer's specified torque to ensure even pressure. Do not overtighten.
- After running the engine, check for any signs of exhaust leaks around the cover.
Troubleshooting & FAQ
How do I know if my old gasket has failed?
Signs of a failed exhaust cover gasket include visible exhaust or water leaks around the cover, an unusually loud exhaust sound, or a noticeable decrease in engine performance. A physical inspection might reveal cracking, brittleness, or disintegration of the old gasket material.
Will this fit my specific Mercury model if it's a 4HP from 1988?
It is very likely to fit if your engine is a 4HP 2-stroke from that year. However, the best way to confirm is to match your old part's number to one of the cross-reference numbers listed: 21-41279M, 27-41279M, 27-99993M, 41279M, or 99993M.
Do I need to use sealant with this gasket?
Typically, this type of gasket is designed to be installed dry without any additional sealant. Applying sealant can sometimes interfere with a proper seal. Always consult your engine's service manual for the recommended procedure.
What is the recommended replacement interval for this gasket?
There is no fixed replacement interval. This gasket should be replaced any time the exhaust cover is removed for service, or if you detect any signs of a leak or failure.
Is there a difference in performance between this and the Yamaha OEM gasket?
Our aftermarket gasket is manufactured to meet or exceed OEM specifications for material integrity and dimensional accuracy. When installed correctly, it will provide a reliable seal with performance equivalent to the original part.
My engine model isn't on the list, but the part looks the same. Can I use it?
We strongly advise against it. Even if a part looks similar, minor differences in dimensions or material can lead to improper fitment, leaks, and potential engine damage. Only purchase if your exact model and year are listed or the OEM part number is a confirmed match.
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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