Power Head Gasket Kit – Fits Yamaha/Mercury F9.9/F8 4-Stroke (Replaces 6G8-W0001-A3-00)
Power Head Gasket Kit – Fits Yamaha/Mercury F9.9/F8 4-Stroke (Replaces 6G8-W0001-A3-00) 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
Power Head Gasket Kit – Fits Yamaha/Mercury F9.9/F8 4-Stroke (Repla...
Product Details
This aftermarket Power Head Gasket Kit provides all necessary seals for servicing the engine block on Yamaha F9.9 and F8BM (1996–1999) and Mercury/Mariner F9.9/F8 (1996–1999) 4-stroke outboards.
It is a direct replacement for Yamaha part numbers 6G8-W0001-A3-00, 6G8-W0001-03-00, and 6G8-W0001-02-00, and serves as an equivalent for Mercury part 27-825847A95.
- Installation Location: Engine Block
- Fuel Compatibility: Gasoline
- Contents: Complete gasket set for a power head overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6G8-W0001-A3-00 | Current OEM part number |
| Yamaha | 6G8-W0001-03-00 | Superseded by 6G8-W0001-A3-00 |
| Yamaha | 6G8-W0001-02-00 | Superseded by 6G8-W0001-03-00 |
| Mercury | 27-825847A95 | Direct cross-reference |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure correct fitment.
For Yamaha Owners: This kit is designed for specific F8 and F9.9 models manufactured between 1996 and 1999. Please verify your exact model name and year.
For Mercury/Mariner Owners: This kit corresponds to OEM part 27-825847A95, fitting F8 and F9.9 models from the 1996–1999 production years.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F9.9 | 9.9 | 4-Stroke | 1996–1999 | 6G8-W0001-A3-00 | Supersedes 6G8-W0001-03-00, 6G8-W0001-02-00 |
| Yamaha | F8BM | 8 | 4-Stroke | 1996–1999 | 6G8-W0001-A3-00 | Supersedes 6G8-W0001-03-00, 6G8-W0001-02-00 |
| Mercury | F9.9 | 9.9 | 4-Stroke | 1996–1999 | 27-825847A95 | |
| Mercury | F8 | 8 | 4-Stroke | 1996–1999 | 27-825847A95 | |
| Mariner | F9.9 | 9.9 | 4-Stroke | 1996–1999 | 27-825847A95 | |
| Mariner | F8 | 8 | 4-Stroke | 1996–1999 | 27-825847A95 |
Technical Specs
- Product Type
- Power Head Gasket Kit
- Installation
- Engine Block
- Fuel Type
- Gasoline
- Dimensions
- 22.5 × 18.0 × 2.0 cm (8.86 × 7.09 × 0.79 in)
- Weight
- 0.13 kg (0.29 lb)
- Other Attributes
- Complete gasket set for F8/F9.9 power head
What’s in the Box
- 1 x Complete Gasket Set (Replaces 6G8-W0001-A3-00)
Installation Notes
The following are general, model-agnostic guidelines. Always consult your engine’s official service manual for detailed procedures, torque specifications, and safety warnings.
- Disconnect the battery and fuel lines to prevent accidental starts or leaks.
- Drain the engine oil and coolant completely to avoid spills.
- Remove the engine cowling, carburetor, flywheel, and any obstructing electrical components, labeling connectors for easier reassembly.
- Carefully unbolt and detach the power head assembly from the engine's midsection.
- Disassemble the cylinder head and block components, keeping all fasteners and parts organized.
- Thoroughly clean all mating surfaces to remove old gasket residue. An appropriate gasket remover and a plastic scraper can prevent damage to aluminum surfaces.
- Install the new gaskets from the kit onto clean, dry surfaces. Follow your service manual's specifications for using sealant, if any.
- Reassemble the power head, ensuring all bolts are tightened to the correct torque value and in the specified sequence.
- Reinstall the power head, reconnect all components, refill fluids, and inspect for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if my power head gaskets are failing?
Common symptoms include engine overheating, a noticeable loss of power or compression, milky or discolored oil (indicating water intrusion), or visible oil/coolant leaks around the cylinder head and block seams.
Does this kit include every seal for the power head?
This is a complete power head gasket kit containing all the essential gaskets for a standard rebuild. It may not include certain oil seals or o-rings that are sold separately. Always compare the contents with your service manual's requirements.
Should I use sealant with these gaskets?
Most gaskets in modern kits are designed for dry installation. However, some specific areas might require a thin application of a specific sealant. Refer to your engine’s official service manual for definitive instructions.
OEM vs. Aftermarket: What's the difference?
This listing is for an aftermarket replacement part, not an OEM component. It has been engineered to meet or exceed OEM-level specifications using comparable materials and manufactured in an ISO 9002 certified facility with rigorous batch inspections.
What are your shipping speeds and costs?
We ship worldwide, with most orders arriving in 5–15 days via standard delivery. Standard shipping is free. Expedited shipping options, where available, are displayed at checkout.
What is your warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal marine use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard policy window for items that are unused and in their original packaging.
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.
