Quicksilver 18643A5 Triangular Flywheel Mount Engine Coupler Kit MerCruiser Alpha Stern Drive

The Quicksilver 18643A5 is an OEM-quality triangular flywheel mount engine coupler kit engineered specifically for select MerCruiser Alpha stern drive applications. Designed and produced to Mercury Marine's original equipment manufacturer specifications, this coupling assembly delivers the precise fit, torque transfer, and reliability that MerCruiser engines demand.

This coupler is designed for use with the 14-inch flywheel featuring a 3-inch crankshaft bolt pattern and 1-piece rear main seal. It is compatible with MerCruiser 3.0L engines (model years 1999–2016), 4.5L MPI, and GM-built V-6 and V-8 engines displacing 305 and 350 cubic inches (model years 1993–2015) paired with MerCruiser Alpha stern drives. Always verify fitment using your engine serial number and consult your service or parts manual for specific applications.

Key Features:

• Genuine Quicksilver OEM replacement coupling assembly
• Triangular flywheel mount design for precise, secure engagement
• Designed for 14-inch flywheels with 3-inch crankshaft bolt pattern
• Compatible with MerCruiser 3.0L (1999–2016), 4.5L MPI, V-6, and V-8 GM engines (305 & 350 cid, 1993–2015)
• For use with MerCruiser Alpha stern drives
• Built to Mercury Marine OEM specifications for maximum performance and longevity
• Backed by Mercury Marine's 1-year factory warranty against defects and workmanship

Quicksilver is a member of the Mercury Marine family of companies and is the premier supplier of Mercury Marine OEM replacement parts and accessories. When reliability on the water matters most, Quicksilver OEM parts provide the confidence of factory-engineered performance.