Sierra Gear Housing Seal Kit 18-0021, Replaces Yamaha 688-W0001-22-00, Fits C75/E75/P75/C80/C85/90/B90/C90 Outboards

The Sierra 18-0021 Gear Housing Seal Kit is a replacement seal set engineered for the lower gear housing of specific Yamaha outboard motors. It replaces the OEM Yamaha part 688-W0001-22-00 and is built to match the fit, form, and function of the original equipment seals it succeeds, making it a direct drop-in choice for a gear housing rebuild or seal replacement job.

This kit fits the Yamaha C75 (1994-99), E75 (1995-00), P75 (1996-99), C80 (1997), C85 (1992-96), 90 (1992-02), B90 (1998-99), and C90 (1997-01) outboard models. Because gear housing seals are a wear item exposed to constant water contact and gear lubricant, replacing them at the correct interval, or any time the lower unit is opened up, helps prevent water intrusion into the gear case and lubricant leakage that can lead to bearing and gear damage. The kit is sold under the Sierra brand, a long-established supplier of outboard replacement parts, and is packaged as a complete set so the seals needed for the job are included together rather than sourced individually.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0021
• Product Type: Gear Housing Seal Kit
• Replaces (OEM): 688-W0001-22-00
• Fitment: Yamaha C75 (1994-99), E75 (1995-00), P75 (1996-99), C80 (1997), C85 (1992-96), 90 (1992-02), B90 (1998-99), C90 (1997-01)
• Weight: 0.36 pounds
• UPC: 808282161132

Fitment

• Yamaha C75 (1994-99)
• Yamaha E75 (1995-00)
• Yamaha P75 (1996-99)
• Yamaha C80 (1997)
• Yamaha C85 (1992-96)
• Yamaha 90 (1992-02)
• Yamaha B90 (1998-99)
• Yamaha C90 (1997-01)

Replaces (OEM)

• 688-W0001-22-00

Frequently Asked Questions

What does the Sierra 18-0021 Gear Housing Seal Kit fit? The 18-0021 kit fits the Yamaha C75 (1994-99), E75 (1995-00), P75 (1996-99), C80 (1997), C85 (1992-96), 90 (1992-02), B90 (1998-99), and C90 (1997-01) outboard models.

What OEM part number does this seal kit replace? It replaces Yamaha OEM part number 688-W0001-22-00, so it is a direct substitute for that original gear housing seal set.

Is the Sierra 18-0021 an OEM part or an aftermarket replacement? It is an aftermarket replacement kit made to match the fit, form, and function of the original Yamaha 688-W0001-22-00 gear housing seal set.

How much does the 18-0021 kit weigh? The Sierra 18-0021 Gear Housing Seal Kit weighs 0.36 pounds.

Will this kit work on a Yamaha 90 outboard? Yes, the 18-0021 kit is designed to fit the Yamaha 90 (1992-02) outboard, along with the C75, E75, P75, C80, C85, B90, and C90 models.

What is included in the 18-0021 kit? The kit includes the gear housing seals needed to service the lower unit of the covered Yamaha outboard models, sold as a Sierra Gear Housing Seal Kit under part number 18-0021.

When should the gear housing seals be replaced? Gear housing seals like those in the 18-0021 kit should be replaced any time the lower unit is opened for service, or when water intrusion or gear lubricant leakage is suspected.

Does the Yamaha C90 use the same seal kit as the C85? Yes, the Sierra 18-0021 Gear Housing Seal Kit covers both the C85 (1992-96) and the C90 (1997-01), along with several other Yamaha models listed in its fitment.

Is the UPC for the 18-0021 kit 808282161132? Yes, the Sierra Gear Housing Seal Kit 18-0021 carries UPC 808282161132.

Can this kit be used on a Yamaha E75 outboard? Yes, the E75 (1995-00) is one of the Yamaha models covered by the Sierra 18-0021 Gear Housing Seal Kit.

What brand makes part number 18-0021? Part number 18-0021 is manufactured by Sierra as a Gear Housing Seal Kit.