Upper Casing Gasket – Fits Yamaha 25-70 HP Outboards (Replaces 6H3-45114-A1-00)
Upper Casing Gasket – Fits Yamaha 25-70 HP Outboards (Replaces 6H3-45114-A1-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Upper Casing Gasket – Fits Yamaha 25-70 HP Outboards (Replaces 6H3-45114-A1-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Upper Casing Gasket – Fits Yamaha 25-70 HP Outboards (Replaces 6H3-45114-A1-00) provides a reliable seal for the upper casing on a range of Yamaha 2-stroke outboards from 25 to 70 HP, primarily covering models from 1984 to 1993. It is engineered to fit specific models including the 25B/BETO, 50G/GEO/GETO, 60F series, 70B series, and E60H/MLHHMH.
It serves as a direct replacement for Yamaha part numbers 6H3-45114-A1-00, 6H3-45114-01-00, and 6H3-45114-00-00, and is an interchange for GLM Marine 38037 and Sierra 18-99046.
- Seals the upper casing to prevent fluid leaks and maintain pressure.
- Designed for use in gasoline-fueled marine environments.
- Direct-fit replacement requires no modifications for installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6H3-45114-A1-00 | Current OEM Part |
| Yamaha | 6H3-45114-01-00 | Superseded by 6H3-45114-A1-00 |
| Yamaha | 6H3-45114-00-00 | Original part, superseded by 6H3-45114-01-00 |
| GLM Marine | 38037 | Aftermarket Equivalent |
| Sierra | 18-99046 | Aftermarket Equivalent |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fitment for this gasket is specific to the following Yamaha outboard models. Please verify your exact model and year before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 50ETK (6B0) | 50 | 2-Stroke | 1993 | 6H3-45114-A1-00 | International model |
| Yamaha | 60FE (6H2) | 60 | 2-Stroke | 1984–1986 | 6H3-45114-A1-00 | International model |
| Yamaha | 60FET (6H2) | 60 | 2-Stroke | 1984–1986 | 6H3-45114-A1-00 | International model |
| Yamaha | 60FEO (6H2) | 60 | 2-Stroke | 1987–1991 | 6H3-45114-A1-00 | International model |
| Yamaha | 60FETO (6H2) | 60 | 2-Stroke | 1987–1991 | 6H3-45114-A1-00 | International model |
| Yamaha | 60F (6H2) | 60 | 2-Stroke | 1993 | 6H3-45114-A1-00 | International model |
| Yamaha | E-60D (6K50) | 60 | 2-Stroke | 1990 | 6H3-45114-A1-00 | International model |
| Yamaha | E60HM (6K5) | 60 | 2-Stroke | 1990–1991 | 6H3-45114-A1-00 | International model |
| Yamaha | E60MHP (6K50) | 60 | 2-Stroke | 1991 | 6H3-45114-A1-00 | International model |
| Yamaha | EHP (6K50) | 2-Stroke | 1991 | 6H3-45114-A1-00 | International model | |
| Yamaha | 70ETN (6H3) | 70 | 2-Stroke | 1984 | 6H3-45114-A1-00 | International model |
| Yamaha | 70B (6H3) | 70 | 2-Stroke | 1985–1991 | 6H3-45114-A1-00 | International model |
| Yamaha | 70B (6H30) | 70 | 2-Stroke | 1990 | 6H3-45114-A1-00 | International model |
| Yamaha | 70CE (6J2) | 70 | 2-Stroke | 1990 | 6H3-45114-A1-00 | International model |
| Yamaha | 70CE (6J20) | 70 | 2-Stroke | 1990 | 6H3-45114-A1-00 | International model |
| Yamaha | 70TRP (6H30) | 70 | 2-Stroke | 1991 | 6H3-45114-A1-00 | International model |
| Yamaha | 70BE (6H3) | 70 | 2-Stroke | 1993 | 6H3-45114-A1-00 | International model |
| Yamaha | 70ETLK | 70 | 2-Stroke | 1985 | 6H3-45114-A1-00 | Outboard model |
| Yamaha | 25B/25BETO | 25 | 2-Stroke | 6H3-45114-A1-00 | Based on aftermarket fit data |
Technical Specs
- Product Type
- Gasket
- Installation
- Upper Casing
- Fuel Type
- Gasoline
- Dimensions
- 10.0" (H) x 15.0" (W) x 0.25" (L)
- Other Technical Attributes
- Seals the upper casing on specific Yamaha outboard models
What’s in the Box
- 1 x Gasket, Upper Casing (6H3-45114-A1-00)
Installation Notes
- Ensure the engine is off, cool, and disconnected from the power source.
- If necessary, drain relevant fluids like oil or coolant to prevent spills during disassembly.
- Carefully remove any cowlings or components obstructing access to the upper casing.
- Remove the bolts securing the components and lift them away to expose the old gasket.
- Peel off the old gasket and use a plastic scraper to gently remove any stuck-on residue from both mating surfaces.
- Clean the surfaces thoroughly with an appropriate solvent to remove all oil, grime, and debris.
- Align the new gasket correctly over the dowels or bolt holes. Do not use sealant unless specified by your engine's service manual.
- Reinstall the upper casing and tighten the bolts in the sequence and to the torque specifications recommended by the manufacturer.
Troubleshooting & FAQ
How do I know if my upper casing gasket is failing?
Signs of a failing upper casing gasket include visible oil or water leaks around the seam, a loss of engine performance, milky or contaminated oil, or engine overheating. A visual inspection for residue or active drips is the first step in diagnosis.
Do I need to apply sealant to this gasket?
Generally, modern gaskets like this one are designed to be installed dry. Applying sealant can sometimes interfere with a proper seal. Always consult your engine’s official service manual for model-specific instructions.
Is this gasket compatible with ethanol-blended marine fuels?
Yes, this aftermarket gasket is made with materials designed to resist degradation from modern gasoline formulations, including those containing ethanol, ensuring a durable and long-lasting seal.
How can I be certain this part fits my engine?
The most reliable method is to match the part number (6H3-45114-A1-00) to the one listed in your engine's parts diagram or service manual. Additionally, use our compatibility table to verify your engine's model and year range.
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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