# 478M0135803 Mercury MerCruiser Impeller | Genuine Quicksilver OEM Part

🔧 Product Description

  

Genuine Quicksilver Water Pump Impeller - Part Number: 47-8M0135803

  

Genuine Quicksilver/Mercury water pump impeller for selected Mercury and Mariner EFI FourStroke outboard lower-unit water pump assemblies. This OEM impeller is designed for the 9.9HP-20HP EFI platform and helps restore correct cooling-water flow through the gearcase pump.

  

⚙️ Key Features

  

• Genuine Quicksilver/Mercury OEM water pump impeller

• Designed for selected Mercury / Mariner EFI FourStroke outboards

• Commonly used on 9.9HP, 10HP, 15HP, 15HP SeaPro and 20HP EFI 2-cylinder applications

• Replaces earlier 47-803748 and later cross-references with 47-8M0214944

• Lightweight 8-blade impeller for small outboard gearcase water pump assemblies

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 47-8M0214944 → Supersedes 47-8M0135803

• 47-8M0135803 → Supersedes 47-803748

• 47-803748 earlier OEM reference

  

OEM / Related Numbers:

  

• 47-8M0135803

• 8M0135803

• 478M0135803

• 47-803748

• 803748

• 47-8M0214944

• 8M0214944

• 334-65021-0 related Tohatsu reference

  

Aftermarket / Verified Equivalents:

  

• Sierra: 18-8921

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury / Mariner 9.9HP-20HP EFI FourStroke outboard lower-unit water pump assemblies

• Mercury / Mariner small outboard gearcase cooling systems using the 803748 / 8M0135803 style impeller

  

Typically suits:

  

• Engine models:

• Mercury 9.9HP EFI 2-cylinder 4-Stroke, serial 1R008146 and up

• Mercury 10HP EFI 2-cylinder 4-Stroke, serial 0R833820 and up

• Mercury 15HP EFI 2-cylinder 4-Stroke, serial 0R833820 and up

• Mercury 15HP EFI SeaPro 2-cylinder 4-Stroke, serial 0R833820 and up

• Mercury 20HP EFI 2-cylinder 4-Stroke, serial 0R833820 and up

• Mercury / Mariner 9.9HP-15HP Super, 2005-2014, serial numbers starting with 0N

• Mercury / Mariner 9.9HP-20HP EFI FourStroke, 2015-2022, 9.9HP serial 1R008146 and up

• Mercury / Mariner 15HP-20HP EFI FourStroke, 2015-2022, serial 0R833820 and up

• Mercury 15HP / 20HP EFI FourStroke outboards, serial 0R833820 and up, 2017 and newer

  

• HP Range: 9.9HP - 20HP

• Engine Type: Mercury / Mariner EFI 2-cylinder 4-stroke outboard lower-unit water pump system

• Year Range: Approximately 2005 onwards for listed 0N Super applications and 2015 onwards for EFI 4-stroke applications, depending on model and serial number

  

🔌 Function

  

The impeller rotates inside the lower-unit water pump housing to draw cooling water through the gearcase and deliver it to the engine cooling system. Correct impeller fitment and condition are essential for maintaining water flow, preventing overheating and protecting 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

## Details

- **Price:** 38.35 AUD
- **Vendor:** Quicksilver
- **Tags:** Quicksilver Marine Parts | Oils Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 38.35 AUD | In stock |

## Images

- 478M0135803 Mercury MerCruiser Impeller | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](www.sawleysautoandmarine.com.au/products/478m0135803-mercury-mercruiser-impeller-genuine-quicksilver-oem-part)
> Updated: 2026-05-17