478M0214944 Mercury MerCruiser 47803748 Impeller | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Water Pump Impeller - Part Number: 47-8M0214944

Genuine Quicksilver/Mercury water pump impeller for selected Mercury and Mariner small outboard lower-unit water pump assemblies. This OEM impeller supersedes the earlier 47-803748 and 47-8M0135803 references and is used across selected 9.9HP-20HP two-stroke, carburetted four-stroke, SeaPro and Command Thrust applications.

⚙️ Key Features

• Genuine Quicksilver/Mercury OEM water pump impeller

• Current service replacement for earlier 47-803748 and 47-8M0135803 impellers

• Designed for selected Mercury / Mariner 9.9HP-20HP small outboard applications

• Used in lower-unit water pump assemblies on two-stroke and four-stroke models

• Helps restore correct cooling-water pressure and tell-tale flow

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 47-8M0214944 → Supersedes 47-8M0135803

• 47-8M0135803 → Supersedes 47-803748

• 47-803748 earlier OEM reference

OEM / Related Numbers:

• 47-8M0214944

• 8M0214944

• 478M0214944

• 47-8M0135803

• 8M0135803

• 478M0135803

• 47-803748

• 803748

• 47803748

• 334-65021-0 related Tohatsu reference

Aftermarket / Verified Equivalents:

• Sierra: 18-8921

• REC: REC47-803748

• AMS: HJ-HJB-J-921

🚤 Compatibility

Commonly used on:

• Mercury / Mariner small outboard lower-unit water pump assemblies

• Mercury / Mariner Command Thrust and SeaPro small outboard cooling systems

• Mercury / Mariner 9.9HP-20HP EFI FourStroke service replacement applications

Typically suits:

• Engine models:

• Mercury 9.9HP Japanese International 2-Stroke, serial 0N059858 and up

• Mercury 15HP Japanese International 2-Stroke, serial 0N001590 and up

• Mercury 18HP Japanese International 2-Stroke, serial 0N001590 and up

• Mercury 8HP Command Thrust 4-Stroke, serial 0R042475 and up

• Mercury 9.9HP Command Thrust 4-Stroke, serial 0R042475 and up

• Mercury 15HP SeaPro 4-Stroke, serial 0R051685 and up

• Mercury 15HP Carb 2-Cylinder 4-Stroke, serial 0R235949 and up

• Mercury 20HP Carb 2-Cylinder 4-Stroke, serial 0R235168 and up

• Mercury 9.9HP-20HP EFI FourStroke service applications replacing 47-8M0135803 / 47-803748

• HP Range: 8HP - 20HP

• Engine Type: Mercury / Mariner small outboard lower-unit water pump system

• Year Range: Application dependent by 0N and 0R serial range, with later EFI FourStroke replacement use where specified by parts diagram

🔌 Function

The impeller rotates inside the lower-unit pump housing to draw water through the gearcase and deliver it into the engine cooling system. Correct impeller condition is essential for water pressure, pump priming and overheating protection.

Common signs of failure:

• Weak or inconsistent tell-tale water stream

• Engine overheating warning

• Reduced cooling-water pressure

• Overheating at idle or low speed

• Cracked, stiff or damaged impeller vanes

• Rubber fragments in the cooling system

• Pump not priming after service or storage

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging