Sierra 18-0677-1-9 Exhaust Riser to Manifold Gasket - Pack of 2

The Sierra 18-0677-1-9 is a marine exhaust riser to manifold gasket set designed to maintain a reliable seal between the exhaust riser and manifold on PCM Ford and PCM GM small block inboard engines. Sold as a pack of two gaskets, this set meets or exceeds original equipment manufacturer specifications to ensure long-lasting performance in demanding marine environments.

Proper riser gaskets are critical to separating the exhaust and cooling water passages. When installing, orient the blocked water passage toward the exhaust outlet (rear of the riser) and the open end toward the front — this ensures adequate water flow over the top of the riser and helps prevent exhaust hose damage from heat.

Key Features:

• Pack of 2 gaskets — ideal for a complete port and starboard replacement
• Compatible with both 3" and 3.5" exhaust risers
• Engineered to meet or exceed OEM specifications
• Direct replacement for Pleasurecraft Marine RM0002
• For use with Sierra 18-1899 risers and 18-1996 manifolds

Replaces / Cross-Reference Part Numbers:

• Pleasurecraft Marine: RM0002
• Sierra: 18-0677, 18-0677-1
• Osco: M0002
• GLM: 33500
• Mallory: 9-65700