GMR12 Aftermarket Marine Exhaust Riser Extension 12 Inch Cast 316 Stainless Steel | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Marine Exhaust Riser Extension 12 Inch Cast 316 Stainless Steel - Part Number: GMR12

A cast AISI 316 stainless-steel threaded exhaust-riser extension providing approximately 11 in of additional vertical rise between a compatible Yanmar/HDI exhaust bend and mixing elbow. It is used where additional waterline clearance is needed to reduce the risk of seawater reaching the engine.

⚙️ Key Features

• Cast AISI 316 stainless-steel construction

• Provides approximately 11 in of added rise

• 1-1/2 BSPT left/right threaded connection

• Compatible with HDI/Yanmar GM, JH, QM and related threaded elbow systems

• Allows the mixer height to be tailored to vessel exhaust geometry

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• GMR12 (height-specific HDI riser-extension reference)

OEM / Related Numbers:

• GMR12

• HDI GM / GMKIT

• HDI JH / JHKIT

• HDI QMKIT

Aftermarket / Verified Equivalents:

• HDI Marine: GMR12

🚤 Compatibility

Commonly used on:

• Threaded Yanmar/HDI marine wet-exhaust installations requiring additional mixer height

Typically suits:

• Engine models:

• Yanmar 1GM / 1GM10

• Yanmar 2GM / 2GM20 / 2GM30

• Yanmar 3GM / 3GM30 / 3HM / 3HM35

• Yanmar 3JH2E / 3JH3E / 3JH5E

• Yanmar 4JHE / 4JH2E

• Yanmar 2QM15 / 2QM20 / 3QM30

• Yanmar YSM12 where a compatible 1-1/2 BSPT system is fitted

• Additional Rise: approximately 11 in

• Overall Length: approximately 12 in

• Thread: 1-1/2 BSPT left/right

• Material: cast AISI 316 stainless steel

🔌 Function

The extension raises the seawater-injection point and wet-exhaust outlet to improve anti-siphon protection and waterline clearance.

Common signs of failure:

• External corrosion, cracking or pin-hole leakage

• Internal carbon, rust or salt restriction

• Cooling water entering the manifold, turbocharger or cylinders

• Steam, reduced cooling-water discharge or an abnormally hot exhaust hose

• Loss of power caused by excessive exhaust back-pressure

📦 Condition

• Brand new aftermarket replacement part

• New and unused

• Supplied in manufacturer or equivalent protective packaging