Sierra 18-0870 Transfer Port Cover Gasket for Mercury/Mariner Outboard

The Sierra 18-0870 Transfer Port Cover Gasket is a precision-engineered replacement gasket designed for Mercury and Mariner outboard engines. This gasket creates an essential airtight seal for the transfer port cover, which is critical for maintaining proper crankcase compression in two-stroke outboard motors.

Key Features:

• Replaces Mercury Marine OEM part number 27-279361
• Machined to match OEM hole and port patterns for precise fitment
• Manufactured from high-quality gasket material designed for marine environments
• Prevents fuel and oil leaks around the transfer port cover
• Helps maintain stable idle and optimal engine performance
• Designed for dry installation in most applications

In two-stroke engines, the transfer port cover gasket maintains the crankcase compression necessary for proper fuel/air mixture transfer from the crankcase to the combustion chamber. A failing gasket can result in visible fuel or oil residue, difficulty achieving stable idle, reduced engine performance, or loss of crankcase compression. Sierra Marine has supplied quality aftermarket marine parts for over 50 years, ensuring reliable performance in harsh marine conditions.