47803748 Mercury MerCruiser Impeller | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Water Pump Impeller - Part Number: 47-803748

Genuine Quicksilver/Mercury water pump impeller for selected Mercury and Mariner small outboard lower-unit water pump assemblies. This OEM impeller is used on compatible 8HP-20HP 2-cylinder 4-stroke and international outboard applications, and has been superseded to the later 8M0214944 service reference.

⚙️ Key Features

• Genuine Quicksilver/Mercury OEM water pump impeller

• Designed for selected Mercury / Mariner 8HP-20HP small outboard applications

• Used on compatible 2-cylinder 4-stroke, SeaPro and international outboards

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

• Superseded through 8M0135803 to the later 8M0214944 service reference

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 47-8M0214944 → Supersedes 47-8M0135803

• 47-8M0135803 → Supersedes 47-803748

• 47-803748 earlier OEM reference

OEM / Related Numbers:

• 47-803748

• 803748

• 47803748

• 47-8M0135803

• 8M0135803

• 478M0135803

• 47-8M0214944

• 8M0214944

• 334-65021-0 related Tohatsu reference

Aftermarket / Verified Equivalents:

• Sierra: 18-8921

• REC: REC47-803748

• Jabsco / aftermarket small-outboard equivalent references where matched by pump dimensions

🚤 Compatibility

Commonly used on:

• Mercury / Mariner 8HP-20HP small outboard lower-unit water pump assemblies

• Mercury / Mariner 2-cylinder 4-stroke and SeaPro cooling systems

• Mercury / Mariner international 9.9HP, 15HP and 18HP applications using 803748-series impeller

Typically suits:

• Engine models:

• Mercury 8HP 4-Stroke 209cc, serial 0P325500 and up

• Mercury 8HP 4-Stroke 209cc, serial 0R042475 and up

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

• Mercury 9.9HP 4-Stroke 209cc, serial 0P325500 and up

• Mercury 9.9HP 4-Stroke 209cc, serial 0R042475 and up

• Mercury 10HP Carb 2-Cylinder 4-Stroke, serial 0R575531 and up

• Mercury 15HP 2-Cylinder International, serial range 0N001590 - 0N055284

• Mercury 15HP 2-Cylinder International, serial 0N055285 and up

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

• Mercury 15HP Carb 2-Cylinder 4-Stroke JCI, serial 0R558208 and up

• Mercury 15HP SeaPro 4-Stroke, serial range 0R051685 - 0R123564

• Mercury 15HP SeaPro 4-Stroke, serial 0R123565 and up

• Mercury 18HP 2-Cylinder International, serial range 0N001590 - 0N055284

• Mercury 18HP 2-Cylinder International, serial 0N055285 and up

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

• Mercury 8HP Command Thrust applications using 47-803748 / 8M0135803 style impeller

• Mercury 9.9HP Command Thrust applications using 47-803748 / 8M0135803 style impeller

• Mercury 9.9HP-15HP Super International applications using the 803748-series impeller

• Mercury 9.9HP-20HP EFI FourStroke applications using 47-8M0135803 / 47-8M0214944 replacement reference

• HP Range: 8HP - 20HP

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

• Year Range: Application dependent; includes listed 0N, 0P and 0R serial-range applications plus later EFI FourStroke service replacement references

🔌 Function

The impeller rotates inside the lower-unit pump housing to draw water through the gearcase and deliver it into the engine cooling system. A correctly fitted impeller helps maintain water pressure, prevents overheating and protects the engine during idle, acceleration and extended running.

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 properly after service or storage

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging