Sierra Mounting Plate to Driveshaft Housing Gasket 18-0334 for Mercury Outboards

The Sierra 18-0334 is a mounting plate to driveshaft housing gasket designed for Mercury outboard motor applications. This gasket seats between the mounting plate and the driveshaft housing to form a tight, reliable seal at that joint, helping keep water out and lubricants in as the lower unit assembly operates. Replacing a worn, cracked, or compressed gasket at this location during a lower unit rebuild, driveshaft housing removal, or general maintenance service helps restore the original factory seal and prevents water intrusion that can lead to corrosion or gearcase damage over time.

Sierra manufactures this gasket to match the fit and function of the original equipment part it replaces, making it a straightforward drop-in choice when servicing the mounting plate and driveshaft housing area on a Mercury outboard. The part ships as a single gasket, part number 18-0334, and is sold individually for one repair.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0334
• Product Type: Mounting Plate to Driveshaft Housing Gasket
• Weight: 0.09 pounds
• Quantity: 1 gasket per package
• UPC: 030999873231

Fitment

• Mercury outboard motors (mounting plate to driveshaft housing joint)

Frequently Asked Questions

What is the Sierra 18-0334 gasket used for? The Sierra 18-0334 is a mounting plate to driveshaft housing gasket that seals the joint between the mounting plate and the driveshaft housing on a Mercury outboard motor, helping prevent water intrusion at that connection.

Does this gasket fit Mercury outboards? Yes, part number 18-0334 is designed for the mounting plate to driveshaft housing joint on Mercury outboard motors.

How many gaskets come in one package? One Sierra 18-0334 gasket is included per package, sold individually for a single repair or rebuild.

How much does the 18-0334 gasket weigh? The Sierra 18-0334 mounting plate to driveshaft housing gasket weighs 0.09 pounds.

Is Sierra 18-0334 a genuine OEM part or an aftermarket replacement? 18-0334 is manufactured by Sierra as a replacement part designed to match the fit and function of the original mounting plate to driveshaft housing gasket.

When would I need to replace this gasket? This gasket should be replaced any time the mounting plate or driveshaft housing is removed for service, or if the existing gasket is torn, cracked, or compressed and no longer sealing properly.

What happens if this gasket fails or is left out during reassembly? A failed or missing gasket at the mounting plate to driveshaft housing joint can allow water to enter the lower unit area, which can lead to corrosion or damage to internal components over time.

Can this gasket be reused after removal? Gaskets like the Sierra 18-0334 are designed for one-time use; once the mounting plate or driveshaft housing has been separated, installing a new gasket such as this one is recommended to maintain a proper seal.

What material is the 18-0334 gasket made from? Sierra part 18-0334 is a gasket designed to seal the mounting plate to driveshaft housing joint on Mercury outboard motors.

Is installation of the 18-0334 gasket straightforward? Yes, the Sierra 18-0334 is a direct-fit gasket that installs between the mounting plate and driveshaft housing during reassembly, following standard gasket installation practice for that joint.