# 144791 Mercury MerCruiser Diaphragm | Genuine Quicksilver OEM Part

🔧 Product Description

  

Genuine Quicksilver Poppet Valve Diaphragm - Part Number: 14479 1

  

A genuine Quicksilver diaphragm used in Mercury V6 cooling system poppet / pressure relief valve assemblies. This diaphragm is used on selected Mercury 2.5L EFI, DFI, Pro XS, XS, Jet and V6 outboards where the cooling-system pressure relief valve diagram specifies 14479 1.

  

⚙️ Key Features

  

• Genuine Quicksilver OEM diaphragm

• Correct Mercury part number 14479 1

• Also commonly written as 144791

• Supersedes earlier 14479 reference

• Used in Mercury V6 poppet / cooling system pressure relief assemblies

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 14479 1 → Supersedes 14479

• 14479 earlier diaphragm reference

  

OEM / Related Numbers:

  

• 14479 1

• 144791

• 14479

• 27-8M0046715 related gasket set reference in some 2.5L powerhead assemblies

• 828343A05 related exhaust divider plate kit reference

• 814754 related seal reference

• 19050 6 related gasket reference

• Poppet valve diaphragm reference for 2.5L Mercury V6 cooling-system assemblies

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury 2.5L V6 cooling system pressure relief / poppet valve assemblies

• Mercury EFI / DFI / Optimax / XS / Pro XS poppet valve diaphragm service

• Mercury Jet and performance V6 outboard cooling systems where 144791 is specified

  

Typically suits:

  

• Engine models:

• Mercury 110 Jet 2.5L - serial 1B690542 to 1B974227

• Mercury 135HP V6 2.5L - serial 0T178500 to 0T800999

• Mercury 135HP V6 2.5L - serial 0T801000 to 1B226999

• Mercury 135HP V6 2.5L - serial 1B227000 to 1B417701

• Mercury 135HP V6 2.5L - serial 1B417702 to 1B737495

• Mercury 140 Jet - serial 0G960500 to 0T178499

• Mercury 150 Pro XS 2.5L - serial 1B690542 to 2B535572

• Mercury 150HP V6 2.5L - serial 0T178500 to 0T800999

• Mercury 150HP V6 2.5L - serial 0T801000 to 1B226999

• Mercury 150HP V6 2.5L - serial 1B227000 to 1B417701

• Mercury 150HP V6 2.5L - serial 1B417702 to 1B580029

• Mercury 175 Pro XS 2.5L - serial 1B516339 to 2B535624

• Mercury 175HP V6 2.5L - serial 0T178500 to 0T800999

• Mercury 175HP V6 2.5L - serial 0T801000 to 1B226999

• Mercury 175HP V6 2.5L - serial 1B227000 to 1B417701

• Mercury 175HP V6 2.5L - serial 1B417702 to 1B508457

• Mercury 200 XS 2.5L - serial 0T235000 to 0T818180

• Mercury 200 XS 2.5L - serial 0T818181 to 1E000796

• Mercury 200 XS 2.5L - serial 1E000797 to 1E002110

• Mercury 200 XS 2.5L ROS - serial 1E050852 to 1E053876

• Mercury 200 XS SST 2.5L - serial 1E050629 to 1E053875

• Mercury 225X EFI Pro Max - serial 0T430254 to 0T819605

• Mercury V-135 - serial 0G960500 to 0T178499

• Mercury V-140 International - serial 0T178500 to 1B226999

• Mercury V-150 - serial 0G960500 to 1B226999

• Mercury V-150 EFI 2.5L - serial 0T409000 to 0T800999

• Mercury V-150 EFI 2.5L - serial 0T801000 to 1B226999

• Mercury V-150 EFI 2.5L - serial 1B227000 and up

• Mercury V-175 EFI 2.5L - serial 0T409000 to 0T800999

• Mercury V-200 - serial 0G960500 to 1B226999

• Mercury V-200 EFI 2.5L - serial 0T409000 to 0T800999

• Mercury V-200 EFI 2.5L - serial 0T801000 to 1B226999

• Mercury V-200 EFI 2.5L - serial 1B227000 and up

• Mercury XR-6 / Magnum III - serial 0G960500 to 1B226999

  

• HP Range: commonly 110 Jet - 225HP where specified

• Engine Type: Mercury 2.5L V6 EFI / DFI / Optimax / performance outboard

• System Type: Cooling system poppet / pressure relief valve diaphragm

  

🔌 Function

  

The diaphragm forms part of the poppet / pressure relief valve assembly. It responds to cooling-system pressure and helps regulate water flow through the engine at different RPM and load conditions.

  

Common signs of failure:

  

• Overheating at idle or high RPM

• Weak or inconsistent cooling water pressure

• Diaphragm torn, stiff or distorted

• Water leakage around poppet valve cover

• Engine temperature fluctuating under load

• Cooling-system service required after salt or debris build-up

  

📦 Condition

  

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 36.2 AUD
- **Vendor:** Quicksilver
- **Tags:** Quicksilver Marine Parts | Oils Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 36.20 AUD | In stock |

## Images

- 144791 Mercury MerCruiser Diaphragm | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](www.sawleysautoandmarine.com.au/products/144791-mercury-mercruiser-diaphragm-genuine-quicksilver-oem-part)
> Updated: 2026-05-17