# 857005A1 Mercury MerCruiser 21857005A1 Diaphragm Kit Fuel Pump | Genuine Quicksilver OEM Part

🔧 Product Description

  

Genuine Quicksilver Fuel Pump Diaphragm Kit - Part Number: 21-857005A1

  

A genuine Quicksilver fuel pump diaphragm kit for selected Mercury and Mariner 2-stroke outboards. This kit services the diaphragm-style fuel pump used to draw fuel from the tank and deliver it to the carburettor or fuel system at the correct pressure.

  

⚙️ Key Features

  

• Genuine Quicksilver OEM fuel pump diaphragm kit

• Correct Mercury part number 21-857005A1

• Replaces earlier 21-42990A10 diaphragm kit reference

• Used across selected 30 Jet through 225HP Mercury / Mariner outboards

• Helps restore fuel pump pressure and reliable fuel delivery

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 21-857005A1 → Supersedes 21-42990A10

• 42990A11 related earlier diaphragm reference

• 42990A10 earlier OEM reference

  

OEM / Related Numbers:

  

• 21-857005A1

• 857005A1

• 21857005A1

• 21-42990A10

• 42990A10

• 42990A11

  

Aftermarket / Verified Equivalents:

  

• Recmar: REC21-42990A10

• No additional aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury / Mariner diaphragm fuel pump applications

  

Typically suits:

  

• Engine models:

• Mercury 30 Jet applications using diaphragm kit 21-857005A1

• Mercury 45 Jet - serial 0D000750 to 0G290584

• Mercury 65 Jet applications using diaphragm kit 21-857005A1

• Mercury 105 Jet applications using diaphragm kit 21-857005A1

• Mercury 140 Jet applications using diaphragm kit 21-857005A1

• Mercury 30HP 2-cylinder fuel pump applications

• Mercury 40HP 2-cylinder fuel pump applications

• Mercury 40HP 3-cylinder fuel pump applications

• Mercury 40HP 4-cylinder fuel pump applications

• Mercury 50HP 3-cylinder fuel pump applications

• Mercury 55HP 3-cylinder fuel pump applications

• Mercury 60HP 3-cylinder fuel pump applications

• Mercury 75HP 3-cylinder fuel pump applications

• Mercury 90HP 3-cylinder fuel pump applications

• Mercury 100HP 4-cylinder fuel pump applications

• Mercury 115HP 4-cylinder fuel pump applications

• Mercury 125HP 4-cylinder fuel pump applications

• Mercury V-135 fuel pump applications

• Mercury V-200 fuel pump applications

• Mercury XR-6 fuel pump applications

• Mercury 200 DFI applications where 21-857005A1 is specified

• Mercury 225HP 3.0L carbureted / EFI / SeaPro applications where specified

  

• HP Range: 30 Jet through 225HP where specified

• Engine Type: Mercury / Mariner 2-stroke outboard

• System Type: Diaphragm fuel pump repair kit

  

🔌 Function

  

The diaphragm kit renews the flexible fuel pump diaphragm and related components so the pump can draw and deliver fuel correctly.

  

Common signs of failure:

  

• Hard starting

• Engine stalls or hesitates under load

• Fuel starvation at higher RPM

• Fuel leaking from the pump body

• Cracked, stiff or torn diaphragm during service

  

📦 Condition

  

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 36.0 AUD
- **Vendor:** Quicksilver
- **Tags:** Quicksilver Marine Parts | Oils Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 36.00 AUD | In stock |

## Images

- 857005A1 Mercury MerCruiser 21857005A1 Diaphragm Kit Fuel Pump | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](www.sawleysautoandmarine.com.au/products/857005a1-mercury-mercruiser-21857005a1-diaphragm-kit-fuel-pump-genuine-quicksilver-oem-part)
> Updated: 2026-05-17