Upper Casing Gasket – Fits Yamaha 75–90HP 2-Stroke Outboards (Replaces 688-45113-A0-00, 688-45113-00-00)
Upper Casing Gasket – Fits Yamaha 75–90HP 2-Stroke Outboards (Replaces 688-45113-A0-00, 688-45113-00-00) 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
Product Details
This high-quality Upper Casing Gasket – Fits Yamaha 75–90HP 2-Stroke Outboards (Replaces 688-45113-A0-00, 688-45113-00-00) ensures a perfect seal for the upper casing on a range of Yamaha 2-stroke outboard engines. It is designed for 3-cylinder models including 75HP (1994–2000), 80HP (1997), 85HP (1989–1996), and 90HP (1984–2009).
It serves as a direct replacement for Yamaha part numbers 688-45113-A0-00 and 688-45113-00-00, and provides an exact interchange for Sierra 18-99151 and Mallory 2251.
- Direct fit design for straightforward installation.
- Engineered for marine environments using a 2-Stroke oil/gas mix.
- Includes one gasket for a complete replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Yamaha | 688-45113-A0-00 | Current OEM part number. | |
| Yamaha | 688-45113-00-00 | 688-45113-A0-00 | Superseded part. |
| Sierra | 18-99151 | Aftermarket cross-reference. | |
| Mallory | 2251 | Aftermarket cross-reference. |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
For Yamaha engines, this gasket fits specific 3-cylinder, 2-stroke models produced between 1984 and 2009.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 3-cylinder | 75 | 2-Stroke | 1994–2000 | 688-45113-A0-00 | Superseded 688-45113-00-00 |
| Yamaha | 3-cylinder | 80 | 2-Stroke | 1997 | 688-45113-A0-00 | Superseded 688-45113-00-00 |
| Yamaha | 3-cylinder | 85 | 2-Stroke | 1989–1996 | 688-45113-A0-00 | Superseded 688-45113-00-00 |
| Yamaha | 3-cylinder | 90 | 2-Stroke | 1984–2009 | 688-45113-A0-00 | Superseded 688-45113-00-00 |
Technical Specs
- Product Type
- Upper Casing Gasket
- Installation
- Direct fit
- Fuel Type
- 2-Stroke Oil/Gas Mix
- Housing Material
- Metal
- Dimensions
- 31.0 cm x 21.0 cm x 0.3 cm
- Other Technical Attributes
- Base/Upper Casing Gasket
What’s in the Box
- 1 x Gasket, Upper Casing (equivalent to 688-45113-A0-00)
Installation Notes
- Ensure the engine is off and cool, and disconnect the battery as a safety precaution.
- Drain relevant fluids to prevent spills during disassembly.
- Remove any components blocking access to the upper casing where the gasket is located.
- Carefully remove the old gasket, taking note of fastener locations.
- Thoroughly clean both mating surfaces to remove any old gasket material, sealant, or corrosion.
- Position the new gasket onto the clean surface, ensuring proper alignment with all bolt holes.
- Reassemble all components in reverse order, tightening fasteners to the manufacturer-specified torque values.
- After reassembly, reconnect the battery and check for any leaks before resuming normal operation.
Troubleshooting & FAQ
How do I know if this gasket will fit my engine?
This gasket is specifically for Yamaha 75HP, 80HP, 85HP, and 90HP 3-cylinder 2-stroke outboards. To ensure a correct fit, please find your engine's model and production year in the "Engine & Model Compatibility" table above.
What are the signs of a bad upper casing gasket?
Common symptoms of a failed gasket include visible water or oil leaks around the casing seam, engine overheating, poor performance, or a noticeable loss of compression.
Do I need to use sealant with this gasket?
This metal gasket is designed to create a seal on its own when installed on clean, flat surfaces. In most cases, sealant is not required. Always consult your engine's service manual for manufacturer-specific recommendations.
What is the difference between part 688-45113-A0-00 and 688-45113-00-00?
The part number 688-45113-A0-00 is the current OEM version that supersedes the older 688-45113-00-00 part. They are functionally identical and fully interchangeable.
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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