Gasket, Lower Base – Fits Yamaha Outboard 115-225 HP (Replaces 6G5-45114-A1-00)
Gasket, Lower Base – Fits Yamaha Outboard 115-225 HP (Replaces 6G5-45114-A1-00) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
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 aftermarket Gasket, Lower Base is designed for a wide range of Yamaha Outboard engines from 115 to 225 HP, covering models from 1984 to 2006 and beyond. It serves as a crucial component for maintaining a tight seal between the lower base and the engine block, preventing leaks and ensuring optimal performance.
It is a direct replacement for Yamaha part numbers 6G5-45114-A1-00, 6G5-45114-A0-00, and 6G5-45114-00-00, and interchanges with Sierra 18-99040.
- Engineered for a direct fit between the lower base and engine block.
- Compatible with both gasoline and oil-injected two-stroke engines.
- Essential for preventing power loss and water or exhaust leaks.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6G5-45114-A1-00 | Current part number. |
| Yamaha | 6G5-45114-A0-00 | Superseded by 6G5-45114-A1-00. |
| Yamaha | 6G5-45114-00-00 | Superseded by 6G5-45114-A0-00. |
| Sierra | 18-99040 | Aftermarket cross-reference. |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Yamaha | 115A/B/ETN/BETO | 115 | 1984–2002 | 6G5-45114-A1-00 | Supersedes 6G5-45114-A0-00 and 6G5-45114-00-00 |
| Yamaha | 115ETLD/ETLF/ETLG/ETLH/ETLJ | 115 | 1986–1990 | 6G5-45114-A1-00 | Including -JD variants |
| Yamaha | 115ETXD/ETXF/ETXG/ETXH/ETXJ | 115 | 1986–1990 | 6G5-45114-A1-00 | Including -DA variants |
| Yamaha | 115TJR/TLR/TXR series | 115 | 1991–2006+ | 6G5-45114-A1-00 | Multiple suffix variants (P through Z, A+) |
| Yamaha | 130BETO | 130 | 1988–2002 | 6G5-45114-A1-00 | |
| Yamaha | 130ETL/ETX series | 130 | 1988–1990 | 6G5-45114-A1-00 | |
| Yamaha | 130TLR/TXR series | 130 | 1991–2004 | 6G5-45114-A1-00 | Multiple suffix variants |
| Yamaha | 140AETO/BETO | 140 | 1984–2002 | 6G5-45114-A1-00 | |
| Yamaha | 150ETN/AETO/CETO/FETO | 150 | 1984–2002 | 6G5-45114-A1-00 | |
| Yamaha | 150ETL/ETX series | 150 | 1984–1990 | 6G5-45114-A1-00 | Including -JD variants |
| Yamaha | 150TJR/TLR/TXR series | 150 | 1991–2005 | 6G5-45114-A1-00 | Multiple variants including VMAX models |
| Yamaha | Z150 models | 150 | 2000–2005 | 6G5-45114-A1-00 | |
| Yamaha | 175AETO | 175 | 1984–2002 | 6G5-45114-A1-00 | |
| Yamaha | 175ETL/ETX series | 175 | 1984–1990 | 6G5-45114-A1-00 | |
| Yamaha | 175TLR/TXR series | 175 | 1991–2004 | 6G5-45114-A1-00 | |
| Yamaha | Z175 models | 175 | 2000–2005 | 6G5-45114-A1-00 | |
| Yamaha | 200ETN/AET-0 | 200 | 1984–2002 | 6G5-45114-A1-00 | |
| Yamaha | 200ETL/ETX series | 200 | 1984–1990 | 6G5-45114-A1-00 | Including -JD variants |
| Yamaha | 200TJR/TLR/TXR series | 200 | 1991–2005 | 6G5-45114-A1-00 | |
| Yamaha | Z200 models | 200 | 2000–2005 | 6G5-45114-A1-00 | |
| Yamaha | 225AETO/DET | 225 | 1987–1997 | 6G5-45114-A1-00 | |
| Yamaha | 225ETL/ETX series | 225 | 1987–1990 | 6G5-45114-A1-00 | |
| Yamaha | 225TLR/TXR series | 225 | 1991–1997 | 6G5-45114-A1-00 | |
| Yamaha | V6 EXCEL/SPECIAL series | 1984–1989 | 6G5-45114-A1-00 |
Technical Specs
- Product Type
- Lower Base Gasket
- Dimensions
- 10.0" H x 15.0" W x 0.25" L
- Weight
- Approximately 0.15 lb (0.068 kg)
- Installation
- Direct fit between lower base and engine block
- Fuel Type
- For both gasoline and oil-injected engines
- Function
- Essential for maintaining a tight seal between the lower base and engine block, preventing leaks and performance loss
- Warranty
- 1-year (Peach Motor Parts)
What’s in the Box
- 1 x Gasket, Lower Base (Replaces 6G5-45114-A1-00)
Installation Notes
- Ensure the engine is off, cool, and disconnected from the battery. Place the outboard in a secure, vertical position.
- Drain the lower unit gearcase oil into an appropriate container.
- Loosen and remove the mounting bolts that secure the lower unit to the midsection. Keep track of bolt lengths and positions.
- Carefully separate the lower unit from the engine's midsection. This may require gentle prying at designated slots.
- Remove the old lower base gasket from the mounting surface.
- Thoroughly clean both mating surfaces on the lower unit and the midsection. Remove all old gasket material, sealant, and corrosion.
- Place the new gasket into position, ensuring all bolt holes and passages align correctly.
- Carefully guide the lower unit back into place, aligning the driveshaft, shift shaft, and water tube. Do not force it.
- Reinstall the mounting bolts and torque them to the manufacturer's specified values in the correct sequence.
- Refill the lower unit with fresh gearcase oil to the correct level.
- Reconnect the battery and test the engine on the water, checking for any signs of water or exhaust leaks around the seam.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific engine model?
Check your engine's model number and year against our compatibility table. The most reliable method is to cross-reference your existing part number with the ones listed in the Part Number Matrix section.
What are the signs of a failing lower base gasket?
Common symptoms include visible water leaking from the seam between the lower unit and the midsection, an unexplained drop in engine performance, or exhaust fumes escaping from the same area. A milky appearance in your gearcase oil can also indicate a water leak.
How often should this gasket be replaced?
This gasket should be replaced any time the lower unit is removed for service, such as during a water pump impeller replacement or other internal repairs. There is no fixed time-based interval, but it is a critical "replace-if-removed" component.
Is this gasket suitable for oil-injected (2-stroke) models?
Yes, this gasket is designed for compatibility with both standard gasoline and oil-injected two-stroke Yamaha outboards within the specified model 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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
