Mercury MerCruiser Exhaust Water Shutter Assembly (Pair)

The Mercury MerCruiser 807166A3 Exhaust Water Shutter Assembly is a genuine OEM replacement kit designed to protect marine engines from water intrusion through the exhaust system. Also known as exhaust flappers or water shutters, these assemblies allow exhaust gases to exit freely while helping prevent following seas, backwash, or water reversion from entering the engine.

Installed downstream of the exhaust elbow and upstream of the Y-pipe, the shutters open during engine operation and close when exhaust flow stops. This simple but critical component can help prevent serious engine damage caused by water ingestion.

Features:

• Genuine Mercury Marine OEM part
• Supplied as a pair (2 shutters per kit)
• Prevents water backflow through the exhaust system
• 2.5″ shutter diameter at the cross pin
• Direct replacement for worn or damaged exhaust flappers
• Designed for MerCruiser sterndrive exhaust systems
• Corrosion and heat-resistant construction

Benefits:

• Helps prevent engine water ingestion
• Reduces risk of corrosion and hydro-lock damage
• Maintains proper exhaust system operation
• OEM fit and reliability
• Easy replacement during exhaust system servicing

Typical Applications:

• Various MerCruiser sterndrive installations
• Mercury Diesel 3.0L engines
• Mercury Diesel 3.6L engines
• Mercury Diesel 4.2L engines
• Additional MerCruiser applications (verify by engine serial number)

Common Names:

• Water Shutter
• Exhaust Flapper
• Exhaust Shutter
• Water Flapper Valve
• Y-Pipe Flapper Assembly

Category:
Exhaust System Components

Tags:
Mercury, MerCruiser, Water Shutter, Exhaust Flapper, Exhaust Shutter, Y-Pipe Flapper, 807166A3, Sterndrive Exhaust, Diesel Exhaust, Water Ingestion Protection, OEM Mercury

SKU:
807166A3