Sierra Transom Seal Kit 18-8219 for MerCruiser Sterndrive Transom Bellows Assembly

The Sierra Transom Seal Kit, part number 18-8219, is a replacement seal kit used to reseal the transom assembly on MerCruiser sterndrive bellows installations. Transom seals are a critical barrier between the outdrive and the boat's transom, keeping water out of the bilge while allowing the drive shaft, shift cable, and exhaust components to pass through the transom plate. Over time these seals dry out, crack, or lose their sealing compression from heat cycling and constant exposure to water and fuel vapor, which can allow water intrusion at the transom. This kit provides the seal components needed to service that connection and restore a watertight fit during transom assembly maintenance or bellows replacement work.

Sierra manufactures this kit to the dimensions and specifications of the original transom seal, so it installs using the same fasteners and mounting points as the assembly it replaces. It is sold as a compact, packaged kit ready for installation as part of a routine sterndrive service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-8219
• Product Name: Transom Seal Kit
• Weight: 4.73 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 808282305307

Fitment

Used in MerCruiser sterndrive transom bellows assemblies.

Replaces (OEM)

No OEM cross-reference numbers are published for this kit.

Frequently Asked Questions

What is the Sierra 18-8219 transom seal kit used for? The Sierra 18-8219 is a transom seal kit used to reseal the transom assembly on a sterndrive boat, sealing the opening where the drive shaft and related components pass through the transom plate.

Does the 18-8219 kit fit MerCruiser sterndrives? Yes, this Sierra transom seal kit is designed for use in MerCruiser sterndrive transom bellows assemblies.

How much does the transom seal kit weigh? The Sierra 18-8219 transom seal kit weighs 4.73 pounds.

What are the dimensions of the 18-8219 kit as packaged? The kit measures 0.39 x 0.39 x 0.39 inches as listed by the manufacturer.

Are there OEM cross-reference numbers for part 18-8219? No OEM cross-reference or replaces numbers are published for the Sierra 18-8219 transom seal kit.

Is the Sierra 18-8219 an original Sierra part or aftermarket? It is a genuine Sierra part, manufacturer part number 18-8219, sold as a dedicated transom seal kit.

When should a transom seal be replaced? A transom seal should be replaced when it shows cracking, hardening, or loss of compression, since a worn seal can allow water to enter the boat at the transom during sterndrive bellows service.

Is installation of the 18-8219 kit a DIY job or does it need a mechanic? Installing the Sierra 18-8219 transom seal kit is typically done as part of a broader sterndrive bellows service, and while experienced boat owners can perform it, it involves working at the transom opening where a watertight seal is critical.

What UPC is associated with the Sierra 18-8219 kit? The Sierra 18-8219 transom seal kit carries UPC 808282305307.

Can this seal kit be used on any boat transom? The Sierra 18-8219 is intended for MerCruiser sterndrive transom bellows assemblies rather than as a universal transom seal.