Sierra 18-2172 MerCruiser GM V6/V8 Engine Coupler Replaces 14505A2

The Sierra 18-2172 Engine Coupler is a heavy-duty aftermarket replacement coupler designed for MerCruiser stern drive applications. This coupler serves as the critical mechanical link between the GM inboard engine and the stern drive unit, transmitting power from the engine flywheel to the drive system.

This part is specifically engineered for use during engine upgrades or replacements — it is required when swapping an older GM V6 or V8 engine with a 2-piece rear main seal and a 3-1/2" crankshaft bolt pattern to a newer 1-piece rear main seal engine with a 3" crankshaft bolt pattern. Without this coupler, the bolt patterns of the old and new engine configurations are incompatible.

Key Features:

• Direct replacement for MerCruiser OEM part number 14505A2
• Designed for MCM GM V-6 and V-8 engines (305 and 350 cid)
• Manufactured to meet or exceed original OEM specifications
• Mounting hardware (studs, washers, and nuts) included
• Cross-references: GLM 11520, Mallory 9-72500, OMC 775495

OEM Cross-Reference Part Numbers: MerCruiser 14505A2 | GLM 11520 | Mallory 9-72500 | OMC 775495

Sierra is the market-leading brand for aftermarket marine engine parts, offering a comprehensive product line backed by a customer satisfaction warranty covering parts and labor. This coupler is a dependable, cost-effective solution for any Pre-Vortec MerCruiser stern drive engine swap or rebuild.