• Free shipping

  • Free help & advice

  • Hassle-free returns

  • Factory direct prices

Flash Sale now on!

FLASHSALE25

Yamaha Gearcase Seal Kit – Fits Yamaha 75-225HP V4/V6 Outboards (Replaces 6G5-W0001-C1-00, 6E5-W0001-F1-00)

Sale price $86.95 Regular price $139.00
Shipping calculated at checkout.

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

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This aftermarket Yamaha Gearcase Seal Kit is engineered to restore the lower unit on a wide range of Yamaha 75-225HP V4/V6 outboard engines, including both 2-stroke and 4-stroke models manufactured between 1984 and 2005.

It serves as a direct replacement for Yamaha OEM part numbers 6G5-W0001-C1-00, 6G5-W0001-21-00, 6E5-W0001-51-00, 6E5-W0001-F1-00, and Sierra part 18-2794-1.

  • Designed for direct OEM-style replacement installation.
  • Constructed from durable rubber and gasket materials.
  • Specifically intended for V4 and V6 outboard lower units.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand Part Number
Yamaha 6G5-W0001-C1-00
Yamaha 6G5-W0001-21-00
Yamaha 6E5-W0001-51-00
Yamaha 6E5-W0001-F1-00
Sierra 18-2794-1

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Compatibility for Yamaha models is listed below.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Yamaha S75 75 2-Stroke 1996 6G5-W0001-C1-00
Yamaha 115HP 115 2-Stroke 1986–2002 6G5-W0001-C1-00
Yamaha 130HP 130 2-Stroke 1988–2002 6G5-W0001-C1-00
Yamaha 150HP 150 2-Stroke 1984–2004 6G5-W0001-C1-00
Yamaha 175HP 175 2-Stroke 1984–2002 6G5-W0001-C1-00
Yamaha 200HP 200 2-Stroke 1984–2006 6G5-W0001-C1-00
Yamaha V-6 Special 220 2-Stroke 1984–86 6G5-W0001-C1-00
Yamaha V-6 Excel 90° 225 2-Stroke 1987–89 6G5-W0001-C1-00
Yamaha 225HP (2.6L) 225 2-Stroke 1990–93, 97 6G5-W0001-C1-00
Yamaha TLRB-TLRD 115 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha TXRB-TXRD 115 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha SX150TXRB-TXRD 150 2-Stroke 2003–2004 6G5-W0001-C1-00
Yamaha Z150TXRB-TXRD 150 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha VZ175TLRB-TLRD 175 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha Z175TXRB-TXRD 175 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha SX200TXRB-TXRD 200 2-Stroke 2003–2005 6G5-W0001-C1-00
Yamaha Z200TXRB-TXRD 200 2-Stroke 2003–2005 6G5-W0001-C1-00

Technical Specs

Product Type
Gearcase/Lower Unit Seal Kit
Installation
OEM Replacement
Application
For V4 and V6 lower units
Fuel Type
Gasoline
Housing Material
Rubber/Gasket Material
Product Dimensions
13.25 in x 9.0 in x 1.25 in
Warranty
Varies by manufacturer

What’s in the Box

  • 1 x Gearcase Seal Kit (Replaces 6G5-W0001-C1-00)

Installation Notes

  1. Begin by draining the gearcase oil completely into a suitable container.
  2. Remove the propeller, noting the order of thrust washers and spacers.
  3. Unbolt the lower unit (gearcase) from the outboard's midsection and carefully lower it.
  4. Disassemble the driveshaft and propeller shaft assemblies as needed to access the old seals. This may require specialized pullers or tools.
  5. Carefully remove all old seals, o-rings, and gaskets, taking care not to scratch the housing surfaces.
  6. Clean the seal seating areas thoroughly to remove any old sealant or corrosion.
  7. Install the new seals using an appropriate seal driver or socket, ensuring they are seated evenly and at the correct depth.
  8. Lubricate new o-rings with marine grease and reassemble all components in reverse order of disassembly.
  9. Torque all fasteners to the manufacturer's specifications.
  10. Refill the gearcase with the correct type and amount of fresh marine gear lube.
  11. Check for leaks before operating the outboard on the water. Professional installation is highly recommended.

Troubleshooting & FAQ

How do I know if this seal kit fits my Yamaha outboard?

This kit is designed for a broad range of Yamaha V4 and V6 engines from 75HP to 225HP (1984–2005). The best way to confirm is to check your engine's model and year against the compatibility chart on this page. Verifying that your existing part number matches one of the cross-referenced numbers (e.g., 6G5-W0001-C1-00) is also a reliable method.

What are common signs that my gearcase seals are failing?

The most common sign is "milky" or creamy-looking gear lube when you drain it, which indicates water intrusion. You might also notice gear oil leaking from the propeller shaft area or a persistent metallic sheen on the water's surface around the lower unit.

Does this kit include all the seals for the entire lower unit?

This is a comprehensive kit containing the primary seals for the driveshaft and propeller shaft areas of the V4/V6 gearcase. However, depending on the specific model and repair, you may need additional individual o-rings or gaskets not included. Always compare the kit contents with your service manual's requirements.

Are any special tools required for installation?

Yes, replacing gearcase seals typically requires specialized tools. These can include a bearing carrier puller, a seal puller, and seal/bearing drivers to ensure proper installation without damaging the new seals or the gearcase housing. We strongly recommend professional installation if you do not have the necessary tools and experience.

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

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • JCB
  • Maestro
  • Mastercard
  • PayPal
  • Union Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.