Sierra 18-2963 Head Gasket, Replaces Johnson/Evinrude 318914, Fits 9.9-14 HP Outboards

The Sierra 18-2963 is a head gasket engineered for Johnson and Evinrude outboard power heads, sealing the cylinder head to the block to maintain compression and prevent coolant or combustion leaks. This is a critical wear part for any outboard rebuild or top-end service, replacing the factory gasket that degrades with heat cycling over time. The gasket is supplied one per package and is built to meet or exceed the performance of the original equipment part it replaces, giving rebuilders confidence that fit and seal quality will match OEM expectations.

Sierra 18-2963 is designed for Johnson/Evinrude outboards rated 9.9 HP (1974-92), 10 HP Commercial (1989-90), and 14 HP (1988-90). It is directly interchangeable with GLM 34140 and Johnson/Evinrude 318914, 320533, and 330818, as well as Mallory 9-63832, so buyers who know any of those cross-reference numbers can confirm this is the correct gasket for their power head. Always match the gasket to your specific HP rating and model year range before ordering to ensure proper cylinder sealing.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2963
• Color: White
• Weight: 0.06 pounds
• Unit Count: 1 gasket per package
• Category: Evinrude Outboard Power Head Gaskets

Fitment

• Johnson/Evinrude 9.9 HP, 1974-92
• Johnson/Evinrude 10 HP Commercial, 1989-90
• Johnson/Evinrude 14 HP, 1988-90

Replaces (OEM)

• GLM 34140
• Johnson/Evinrude Outboard 318914
• Johnson/Evinrude Outboard 320533
• Johnson/Evinrude Outboard 330818
• Mallory 9-63832

Frequently Asked Questions

What outboards does the Sierra 18-2963 head gasket fit? It fits Johnson/Evinrude outboards rated 9.9 HP (1974-92), 10 HP Commercial (1989-90), and 14 HP (1988-90).

Is the Sierra 18-2963 the same as GLM 34140? Yes, GLM 34140 is a direct cross-reference to the Sierra 18-2963 head gasket, meaning either part number will fit the same Johnson/Evinrude applications.

What OEM numbers does 18-2963 replace? Sierra 18-2963 replaces Johnson/Evinrude Outboard 318914, 320533, and 330818, as well as Mallory 9-63832.

How many gaskets come in one package of 18-2963? One Sierra 18-2963 head gasket is included per package.

How much does the Sierra 18-2963 head gasket weigh? The Sierra 18-2963 head gasket weighs 0.06 pounds.

What color is the Sierra 18-2963 gasket? The Sierra 18-2963 head gasket is white.

Will the Sierra 18-2963 gasket fit a 1985 Johnson/Evinrude 9.9 HP? Sierra lists the 18-2963 as fitting Johnson/Evinrude 9.9 HP outboards from 1974 to 1992, so a 1985 model falls within that fitment range.

Is Sierra 18-2963 a genuine OEM part or aftermarket? The 18-2963 is a Sierra-brand aftermarket head gasket that is built to meet or exceed the performance of the original equipment gasket it replaces, such as Johnson/Evinrude 318914.

Does the 18-2963 gasket fit the 10 HP Commercial outboard? Yes, Sierra 18-2963 fits the Johnson/Evinrude 10 HP Commercial outboard for model years 1989-90.

What is included when I order the Sierra 18-2963? Each order includes one Sierra 18-2963 head gasket; no additional hardware or gaskets are included in the package.