Sierra 18-0987-9 Throttle Body to Manifold Gasket, Replaces 321479, Fits 25 & 35 HP Outboards, Pack of 2

The Sierra 18-0987-9 is a throttle body to manifold gasket for 25 HP and 35 HP outboard engines, sold as a pack of 2. This gasket seals the mating surface between the throttle body and the intake manifold, maintaining a proper air/fuel seal at this connection. It is built to meet or exceed original equipment quality, making it a direct-fit replacement for the OEM gasket it supersedes.

Because it ships two to a pack, the 18-0987-9 covers a full gasket replacement plus a spare, or two separate jobs, without needing to order twice. Replacing this gasket during a throttle body service or manifold removal helps restore a tight seal and prevent air leaks that can affect engine performance. The part is identified by Sierra part number 18-0987-9 and directly replaces OEM part number 321479.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0987-9
• Product Type: Throttle Body to Manifold Gasket
• Package Quantity: 2 gaskets per pack
• Engine Fitment: 25 HP & 35 HP outboard engines
• Weight: 0.04 pounds
• UPC: 808282162245
• Replaces (OEM): 321479

Fitment

• 25 HP outboard engines
• 35 HP outboard engines

Replaces (OEM)

• 321479

Frequently Asked Questions

What engines does the Sierra 18-0987-9 gasket fit? The Sierra 18-0987-9 throttle body to manifold gasket fits 25 HP and 35 HP outboard engines.

How many gaskets come in this pack? Sierra 18-0987-9 is sold as a pack of 2 gaskets, not a single piece.

What OEM part number does 18-0987-9 replace? It directly replaces OEM part number 321479.

Where does this gasket get installed? This gasket seals the mating surface between the throttle body and the intake manifold on 25 HP and 35 HP outboard engines.

Is the Sierra 18-0987-9 an OEM part or aftermarket? It is an aftermarket gasket manufactured by Sierra to meet or exceed the quality of the original equipment part it replaces, OEM 321479.

How much does this gasket set weigh? The Sierra 18-0987-9 pack of 2 gaskets weighs 0.04 pounds.

What is the UPC for this part? The UPC for Sierra 18-0987-9 is 808282162245.

Can I use one gasket from the pack and save the other? Yes, Sierra 18-0987-9 ships two gaskets per pack, so one can be installed now and the second kept as a spare or used on a second engine.

Does 18-0987-9 fit engines other than 25 HP and 35 HP models? Sierra lists the 18-0987-9 gasket as fitting 25 HP and 35 HP outboard engines specifically.

Why replace the throttle body to manifold gasket? Replacing the throttle body to manifold gasket, such as the Sierra 18-0987-9, restores the seal between these components and helps prevent leaks during throttle body or manifold service on 25 HP and 35 HP outboards.