Sierra 18-3891 Head Gasket for Yamaha Outboard, Replaces 61A-11181-00-A0

The Sierra 18-3891 Head Gasket is a replacement head gasket engineered for Yamaha outboard motors. It seals the mating surface between the cylinder head and powerhead, maintaining proper compression and preventing coolant or combustion leaks at the head joint. Each package includes one gasket, and Sierra states that every Sierra product meets or exceeds the original equipment part it replaces, making the 18-3891 a direct functional substitute for the factory Yamaha head gasket.

This gasket is designed for installation whenever the cylinder head is removed for service, such as during a powerhead rebuild, decarbonizing, or repair of a blown head gasket. Installing a new gasket at reassembly, rather than reusing the old one, helps restore a proper seal and compression.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3891
• Product Name: Head Gasket
• Category: Yamaha Outboard Head Gaskets
• Quantity per Package: 1 gasket
• Weight: 0.26 pounds
• UPC: 030999753731

Fitment

• Yamaha outboard motors

Replaces (OEM)

• 61A-11181-00-A0

Frequently Asked Questions

What is the Sierra 18-3891 used for? It is a head gasket that seals the joint between the cylinder head and powerhead on a Yamaha outboard motor, maintaining compression and preventing leaks at that surface.

Which OEM part number does the 18-3891 replace? The Sierra 18-3891 corresponds to Yamaha OEM part number 61A-11181-00-A0.

How many gaskets come in one package? One Sierra 18-3891 head gasket is included per package.

Is the Sierra 18-3891 a genuine Yamaha part or aftermarket? The 18-3891 is a Sierra-manufactured aftermarket replacement, not a genuine Yamaha-branded part, though Sierra states it meets or exceeds the original equipment part it replaces.

Does the 18-3891 fit all Yamaha outboards? The 18-3891 is designed for Yamaha outboard motor applications; consult the OEM cross-reference number 61A-11181-00-A0 to confirm fit against your motor's original gasket part number.

When should this head gasket be replaced? The 18-3891 should be installed as a new gasket any time the cylinder head is removed from the powerhead, such as during a rebuild or repair, rather than reusing the old gasket.

How much does the Sierra 18-3891 weigh? The Sierra 18-3891 head gasket weighs 0.26 pounds.

What is the UPC for the Sierra 18-3891? The UPC for the Sierra 18-3891 Head Gasket is 030999753731.

Can the 18-3891 be reused after removal? No, a head gasket like the 18-3891 is a single-use sealing component and should be replaced with a new one any time the head is removed.

What brand makes part number 18-3891? Part number 18-3891 is manufactured by Sierra.