Sierra 18-4263 Brass Pipe Plug, 1/8 inch NPT, Replaces Mercury 22-328021

The Sierra 18-4263 is a brass pipe plug sized for 1/8 inch - 27 NPT threads, used to seal unused ports on marine exhaust manifolds, risers, and other threaded fittings. It is machined from brass for corrosion resistance in a marine engine environment and is a small, single-piece hardware item meant to be installed with pipe sealant rather than thread tape alone, since NPT tapered threads rely on a sealant such as Teflon-rated pipe dope to achieve a leak-free seal.

This plug is commonly used as a service and replacement part for engine and exhaust hardware where a factory plug has corroded, stripped, or been removed for inspection. It is also supplied as one of the included components in certain riser and manifold kits, alongside other Sierra parts, for installers who need a matching plug on hand during a rebuild. Because it is a simple sealing plug rather than a machine-specific part, it is used across a range of Chrysler, Mercury, and Mercruiser marine engine applications that call for a 1/8 inch NPT brass plug.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-4263
• Product Type: Pipe Plug
• Material: Brass
• Thread Size: 1/8 inch - 27 NPT
• Thread Type: NPT
• Exterior Finish: Machined
• Item Dimensions (L x W x H): 0.39 x 0.39 x 0.39 inches
• Weight: 0.03 pounds
• Number of Pieces: 1
• UPC: 808282259129
• OEM Cross-References: FI5810151, F700633, 22-328022, 22-328021, GLM 21893, 22-841908, 22-32802, 22-30139

Fitment

Universal 1/8 inch - 27 NPT threaded port application; no engine-specific fitment is specified.

Replaces (OEM)

• Chrysler FI5810151
• Chrysler F700633
• 22-328022
• 22-328021
• GLM 21893
• Mercruiser 22-841908
• 22-32802
• Mercury 22-30139

Frequently Asked Questions

What thread size does the Sierra 18-4263 pipe plug use? The Sierra 18-4263 has a 1/8 inch - 27 NPT tapered pipe thread.

What material is the 18-4263 pipe plug made from? It is machined from brass, chosen for its corrosion resistance in marine exhaust and engine hardware applications.

Do I need sealant to install the 18-4263 plug? Yes, a pipe sealant with Teflon is recommended on the threads of the 18-4263 to ensure a leak-free seal, since NPT tapered threads depend on sealant rather than thread tape alone.

Is the Sierra 18-4263 a genuine OEM part or an aftermarket replacement? The 18-4263 is a Sierra aftermarket replacement plug manufactured to meet or exceed the original equipment part it replaces.

What OEM part numbers does the 18-4263 cross-reference to? It is interchangeable with Chrysler FI5810151 and F700633, GLM 21893, Mercruiser 22-841908 and 22-32802, Mercury 22-30139, and 22-328021 / 22-328022.

How much does the 18-4263 pipe plug weigh? The Sierra 18-4263 weighs 0.03 pounds.

What are the dimensions of the 18-4263 plug? It measures 0.39 x 0.39 x 0.39 inches.

How many plugs come in a package? Each package of the Sierra 18-4263 includes one pipe plug.

What finish does the 18-4263 plug have? The plug has a machined brass finish.

Is the 18-4263 plug included with any other Sierra parts? Yes, the 18-4263 is supplied as one of the plugs included with certain Sierra exhaust riser and manifold kits, alongside parts such as 18-0897 and 18-4258.

Can the 18-4263 be reused after removal? Because NPT pipe plugs rely on sealant for a leak-free fit, it is best practice to apply fresh pipe sealant to the 18-4263 each time it is reinstalled rather than reusing old sealant.