865952-C 866003A9 Mercruiser Exhaust Elbow | Genuine Used Part

🔧 Product Description

Genuine MerCruiser Cast Exhaust Elbow Assembly - Service Part Number: 866003A9

A genuine MerCruiser exhaust elbow identified by service assembly number 866003A9 and casting number 865952-C.

The elbow forms part of the marine wet-exhaust system, receiving hot exhaust gases from the manifold or exhaust collector and introducing cooling water before the exhaust enters the downstream hose, Y-pipe or transom exhaust system.

Number 865952-C is the cast or engineering number moulded into the component. It should not be represented as a separate supersession unless it appears as a service number in the engine parts catalogue.

⚙️ Key Features

• Genuine Mercury MerCruiser cast exhaust component
• Service assembly reference 866003A9
• Casting or engineering reference 865952-C
• Water-jacketed marine exhaust construction
• Designed for the matching MerCruiser manifold and exhaust outlet pattern

🚤 Compatibility

Commonly used on

• MerCruiser wet-exhaust installations whose OEM diagram specifies 866003A9
• Petrol sterndrive and inboard applications using casting 865952-C

Typically suits

• MerCruiser engine packages using exhaust-elbow assembly 866003A9
• Installations with the matching manifold flange, water connections and exhaust outlet
• Alpha or Bravo drive installations only where the engine exhaust diagram lists this assembly
• Engine Type: MerCruiser petrol marine engine
• Exhaust Type: Water-cooled wet exhaust
• Fitment Control: Engine model, serial number and exhaust-manifold configuration

🔌 Function

The exhaust elbow directs exhaust gases away from the manifold and mixes cooling water into the exhaust stream to lower downstream exhaust temperature.

⚠️ Common Signs of Failure

• Internal water jackets blocked by rust or scale
• Cooling water leaks into the exhaust passage
• External cracking or heavy corrosion
• Burnt or leaking elbow-to-manifold gasket
• Steam, overheating or restricted exhaust flow
• Water enters an engine cylinder through an internally damaged elbow

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 866003A9 documented service-assembly reference
• 865952-C casting or engineering number on the elbow
• No confirmed linear supersession between 865952-C and 866003A9

OEM / Related Numbers

• 866003A9
• 866003-A9
• 865952-C
• 865952C
• Related exhaust-elbow gasket
• Related exhaust-manifold outlet gasket
• Related water-injection hose and clamps
• Related MerCruiser exhaust Y-pipe or collector

Aftermarket / Verified Equivalents

• No verified branded direct replacement for complete assembly 866003A9
• Generic MerCruiser elbows with a similar appearance are not verified equivalents
• Replacement must use the same water-passage layout, bolt spacing and outlet configuration

📦 Condition

• Genuine used part
• Removed from running engine where applicable
• In good working condition unless otherwise stated