# 478M0204712 Mercury MerCruiser Impeller | Genuine Quicksilver OEM Part

## 🔧 Product Description

**Genuine Quicksilver Water Pump Impeller - Part Number: 47-8M0204712**

Genuine Quicksilver/Mercury water pump impeller for selected Mercury and Mariner 15HP-25HP outboard lower-unit water pump applications. This OEM impeller replaces earlier 85089-series Mercury impeller references and helps restore proper cooling-water flow through the gearcase pump.

## ⚙️ Key Features

-   Genuine Quicksilver/Mercury OEM water pump impeller
-   Designed for selected Mercury / Mariner 15HP-25HP outboards
-   Direct replacement for earlier 85089-series impeller references
-   Used in compatible lower-unit water pump assemblies
-   Helps restore tell-tale flow, cooling-water pressure and pump priming

## 🚤 Compatibility

### Commonly used on

-   Mercury / Mariner 15HP-25HP outboard lower-unit water pump assemblies
-   Small-to-mid Mercury / Mariner outboard gearcase cooling systems using the 85089-series impeller

### Typically suits

-   Engine models:
-   Mercury / Mariner 15HP 2-Stroke outboard applications using 85089-series water pump impeller
-   Mercury / Mariner 18HP 2-Stroke outboard applications using 85089-series water pump impeller
-   Mercury / Mariner 20HP 2-Stroke outboard applications using 85089-series water pump impeller
-   Mercury / Mariner 25HP 2-Stroke outboard applications using 85089-series water pump impeller
-   Mercury / Mariner 15HP-25HP small outboard gearcase applications where the parts diagram specifies 47-8M0204712
-   Mercury / Mariner 15HP-25HP service applications replacing 47-85089, 47-850891, 47-8508910, 47-8508920, 47-850893, 47-8M0024502 or 47-8M0027792
-   HP Range: 15HP - 25HP
-   Engine Type: Mercury / Mariner outboard lower-unit water pump system
-   Year Range: Application dependent by model and serial number; confirm against the gearcase water pump parts diagram when replacing earlier 85089-series impellers

## 🔌 Function

The impeller draws water through the lower unit and pushes it into the engine cooling system. A correct impeller helps maintain water pressure, reduces overheating risk and supports reliable cooling at idle, low speed and operating RPM.

## ⚠️ Common Signs of Failure

-   Weak or inconsistent tell-tale water stream
-   Engine overheating warning
-   Pump not priming after service
-   Cracked, stiff or missing impeller vanes
-   Reduced cooling-water pressure
-   Rubber fragments found in the cooling system

## 🔄 Supersession & Cross Reference

### OEM Supersession Chain

-   47-8M0204712 → Supersedes 47-8M0027792
-   47-8M0027792 → Supersedes 47-8M0024502
-   47-8M0024502 → Supersedes 47-850893
-   47-850893 → Supersedes 47-8508920
-   47-8508920 → Supersedes 47-8508910
-   47-8508910 → Supersedes 47-850891
-   47-850891 → Supersedes 47-85089
-   47-85089 earlier OEM reference

### OEM / Related Numbers

-   47-8M0204712
-   8M0204712
-   478M0204712
-   47-8M0027792
-   8M0027792
-   47-8M0024502
-   8M0024502
-   47-850893
-   850893
-   47-8508920
-   8508920
-   47-8508910
-   8508910
-   47-850891
-   850891
-   47-85089
-   85089

### Aftermarket / Verified Equivalents

-   REC: REC47-85089
-   Sierra: 18-3099 where matched by pump dimensions and application
-   Mallory: 9-45310 where matched by pump dimensions and application

## 📦 Condition

-   Genuine Quicksilver part
-   Brand new
-   Supplied in original or equivalent packaging

## Details

- **Price:** 58.15 AUD
- **Vendor:** Quicksilver
- **Type:** Pumps
- **Tags:** Quicksilver Marine Parts | Oils, Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 58.15 AUD | In stock |

## Images

- 478M0204712 Mercury MerCruiser Impeller | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/478m0204712-mercury-mercruiser-impeller-genuine-quicksilver-oem-part)
> Updated: 2026-09-18