Sierra 18-0720 Closed Dry-Joint Gasket, Replaces Mercruiser 27-864549A02, Fits 4.3L Alpha/Bravo (2002 and Newer)

The Sierra 18-0720 is a Closed Dry-Joint Gasket engineered for MerCruiser 4.3L Alpha and Bravo drive applications built 2002 and newer without engine catalyst. It seals the joint between the dry-joint exhaust manifold and riser, a design used on modern MerCruiser sterndrive engines to keep raw cooling water separated from the exhaust path at the manifold-to-riser connection. The gasket is round in shape and finished in white, and is sized to mate directly with the Sierra 18-1843 manifold and Sierra 18-1845 riser, making it a straightforward drop-in replacement when servicing or resealing this joint.

This is the "Closed" style gasket in Sierra's dry-joint gasket lineup; the same part family is also offered in Open (18-0721) and Restricted (18-0722) configurations, so it is important to confirm the closed-style gasket is the correct one for your manifold-to-riser setup before ordering. The gasket directly replaces Mercruiser 27-864549A02 and 27-864549A01, letting owners source a Sierra-branded equivalent without hunting down the original Mercruiser part number. As with all Sierra engine and drive parts, it is built to meet or exceed the specifications of the original equipment part it replaces and is designed to hold up to the heat and corrosion exposure of the marine exhaust environment.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0720
• Type: Closed Dry-Joint Gasket
• Color: White
• Shape: Round
• Weight: 0.25 pounds
• UPC: 808282359447
• Fitment: MerCruiser 4.3L Alpha/Bravo, 2002 and newer, without engine catalyst
• Use With: Manifold Sierra Part Number 18-1843 and Riser Sierra Part Number 18-1845
• Related Variants: Open Dry-Joint Gasket 18-0721, Restricted Dry-Joint Gasket 18-0722

Fitment

• MerCruiser 4.3L Alpha/Bravo, 2002 and newer, without engine catalyst

Replaces (OEM)

• Mercruiser 27-864549A02
• Mercruiser 27-864549A01

Frequently Asked Questions

What does the Sierra 18-0720 gasket fit? The Sierra 18-0720 Closed Dry-Joint Gasket fits MerCruiser 4.3L Alpha and Bravo drive applications built 2002 and newer without engine catalyst.

What Mercruiser part numbers does 18-0720 replace? It replaces Mercruiser 27-864549A02 and 27-864549A01.

Is the 18-0720 an Open, Closed, or Restricted style gasket? It is the Closed style dry-joint gasket. Sierra also offers this same gasket in an Open style (18-0721) and a Restricted style (18-0722), so confirm which style your manifold-to-riser joint requires before ordering.

What manifold and riser does this gasket pair with? The 18-0720 gasket is used with the Sierra 18-1843 manifold and Sierra 18-1845 riser at the dry-joint connection between them.

What color and shape is the 18-0720 gasket? It is a round gasket finished in white.

How much does the 18-0720 gasket weigh? The Sierra 18-0720 Closed Dry-Joint Gasket weighs 0.25 pounds.

Is the Sierra 18-0720 gasket genuine Sierra or an aftermarket copy? It is a genuine Sierra-branded part, engineered to meet or exceed the specifications of the original Mercruiser equipment it replaces.

What is the difference between 18-0720, 18-0721, and 18-0722? 18-0720 is the Closed style dry-joint gasket, 18-0721 is the Open style, and 18-0722 is the Restricted style; all three are part of the same dry-joint gasket family but are not interchangeable, so the correct style must be matched to the manifold-and-riser setup.

Does the 18-0720 gasket work on engines with a catalyst? No, the 18-0720 is fitted to MerCruiser 4.3L Alpha/Bravo applications 2002 and newer without engine catalyst.

What is included when I order the 18-0720? You receive one Sierra 18-0720 Closed Dry-Joint Gasket, sized for the joint between the 18-1843 manifold and 18-1845 riser.