Sierra 18-0320 Reed Block Gasket - Cross Reference Mercury 27-13937

The Sierra 18-0320 is a reed block gasket built for outboard engine service, sealing the mating surface between the reed valve block and the powerhead to maintain proper crankcase compression and prevent air or fuel leaks at the joint. It is manufactured from a glass-based gasket material designed to hold a consistent seal under the heat cycling and vibration typical of outboard operation. Each Sierra gasket is engineered to meet or exceed the quality of the original equipment part it replaces, making it a straightforward direct-fit replacement during a reed block rebuild, powerhead service, or routine maintenance. The 18-0320 is a single-piece gasket supplied as one unit, sized to match the reed block gasket used across a range of Mercury outboard applications that call for this specific part. Because it corresponds to several historical OEM and aftermarket part numbers, it is commonly sourced as a replacement whenever an older reference number is found stamped on the block or listed in a parts diagram. Installers should confirm the old gasket's dimensions and bolt pattern against the 18-0320 before ordering, and always install a new gasket rather than reusing the old one to ensure a proper seal.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0320
• Item Type: Reed Block Gasket
• Material: Glass
• Color: Multi-coloured
• Unit Count: 1 gasket
• Weight: 0.02 pounds
• UPC: 030999873101
• OEM Cross-Reference: GLM 32220, Mallory 9-60061, Mercury 27-13937-6, 27-139374, 27-139372, 27-13937

Replaces (OEM)

• GLM 32220
• Mallory 9-60061
• Mercury 27-13937-6
• Mercury 27-139374
• Mercury 27-139372
• Mercury 27-13937

Frequently Asked Questions

What is the Sierra 18-0320 used for? The Sierra 18-0320 is a reed block gasket that seals the joint between the reed valve block and the powerhead on applicable outboard engines, maintaining proper crankcase sealing.

Is the 18-0320 gasket the same as Mercury 27-13937? Yes, the Sierra 18-0320 Reed Block Gasket is a direct cross-reference for Mercury 27-13937, 27-13937-6, 27-139374, and 27-139372, along with GLM 32220 and Mallory 9-60061.

What material is the 18-0320 reed block gasket made from? It is made from a glass-based gasket material designed to hold a consistent seal under engine heat and vibration.

How many gaskets are included with part number 18-0320? One reed block gasket is included per unit count for the Sierra 18-0320.

How much does the Sierra 18-0320 gasket weigh? It weighs 0.02 pounds.

Does the Sierra 18-0320 meet original equipment quality? Sierra states this gasket meets or exceeds the quality of the original equipment part it replaces, making the 18-0320 a reliable equivalent to OEM.

Can I reuse my old reed block gasket instead of installing the 18-0320? No, a gasket should not be reused once removed; installing a new Sierra 18-0320 ensures a proper seal at the reed block joint.

What color is the 18-0320 gasket? The gasket has a multi-coloured appearance, consistent with its glass-based gasket material.

Is the Sierra 18-0320 an aftermarket or genuine Mercury part? The 18-0320 is a Sierra-brand aftermarket gasket engineered as a cross-reference equivalent to the Mercury 27-13937 series parts, not a Mercury-branded part.

What is the UPC for the Sierra 18-0320 reed block gasket? The UPC is 030999873101.