Sierra 18-29451-9 Drain Screw Gasket, 50-Pack, Replaces 12-20260, F8077, F8186, for Lower Units and Sea Water Pumps

The Sierra 18-29451-9 Drain Screw Gasket is a replacement sealing gasket sold in a pack of 50, designed for use with Sierra's 18-2944 Drain Screw. It is used in most lower units and sea water pumps, where it seals the drain screw against water and gear lube leakage during service and maintenance. The gasket is round in shape, finished in white, and built with marine grade materials to withstand exposure to water and lubricants inside the lower unit and pump housing. Because drain and fill screws are removed routinely during gear lube changes and winterization, the gasket underneath should be replaced each time rather than reused, and having a 50-count pack on hand means a fresh gasket is always available for the next service interval. This part is cataloged as a Johnson Outboard Gasket Set item, reflecting its common use across Johnson-family lower unit and pump service. Always confirm the drain screw and housing dimensions on your unit match before installing, since gaskets are sized to a specific screw.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-29451-9
• Product Type: Drain Screw Gasket
• Package Quantity: 50 gaskets per pack
• Color: White
• Shape: Round
• Material: Marine grade material
• Weight: 0.5 pounds
• Designed For Use With: Sierra 18-2944 Drain Screw
• Application: Used in most lower units and sea water pumps
• Category: Johnson Outboard Gasket Set
• UPC: 808282180362

Fitment

• Used in most lower units and sea water pumps; designed for use with the Sierra 18-2944 Drain Screw

Replaces (OEM)

• 12-20260
• 12-19183
• 12-191832
• 12-191833
• F50556
• F8077
• F8186

Frequently Asked Questions

What is the Sierra 18-29451-9 gasket used for? It is a drain screw gasket used in most lower units and sea water pumps, sealing the drain screw threads to prevent leaks after service.

How many gaskets come in a pack? The 18-29451-9 pack contains 50 drain screw gaskets, enough for many service intervals.

Which drain screw does this gasket fit? This gasket is designed for use with Sierra's 18-2944 Drain Screw.

What OEM part numbers does the 18-29451-9 gasket replace? It replaces OEM numbers 12-20260, 12-19183, 12-191832, 12-191833, F50556, F8077, and F8186.

What material is the gasket made from? The Sierra 18-29451-9 gasket is built with marine grade material suited to sealing against water and gear lube exposure.

What color and shape is this gasket? It is round in shape and white in color.

How much does a pack weigh? A pack of 50 Sierra 18-29451-9 gaskets weighs 0.5 pounds.

Should the drain screw gasket be reused after removing the drain screw? No; a new gasket should be installed each time the drain screw is removed, which is why the 18-29451-9 is sold in a 50-pack for repeated service.

Is this a genuine Sierra part? Yes, part number 18-29451-9 is a genuine Sierra drain screw gasket, not a generic aftermarket substitute.

What is included in the package? The package includes 50 drain screw gaskets and nothing else; the drain screw itself (18-2944) is sold separately.

Will this gasket fit any lower unit or sea water pump? The 18-29451-9 gasket is used in most lower units and sea water pumps, but fit should be confirmed against your specific drain screw before ordering.