# 12-20553 Mercury MerCruiser Washer | Genuine Quicksilver OEM Part

🔧 Product Description

  

Genuine Quicksilver Powerhead Stud Washer - Part Number: 12-20553

  

A genuine Quicksilver plain washer used on Mercury and Mariner powerhead stud, exhaust plate and driveshaft housing assemblies. This .406 x .734 x .063 washer is commonly used with powerhead stud nuts on inline, V6, EFI, DFI / OptiMax, Jet and Racing outboard applications.

  

⚙️ Key Features

  

• Genuine Quicksilver OEM washer

• Correct Mercury part number 12-20553

• Size: .406 x .734 x .063

• Common powerhead stud washer application

• Replaces earlier 12-25970 washer reference in selected diagrams

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 12-20553 → Replaces 12-25970 where specified

• 12-25970 earlier powerhead stud washer reference

  

OEM / Related Numbers:

  

• 12-20553

• 20553

• 12-25970 related earlier washer reference

• 11-69254 related powerhead stud nut

• 27-991734 related driveshaft housing gasket

• 27-991764 related powerhead gasket

  

Aftermarket / Verified Equivalents:

  

• No direct aftermarket equivalent preferred over OEM for powerhead stud hardware

• OMC / Volvo / other cross-reference listings exist for selected non-Mercury V6 screw washer applications, but Mercury fitment should be confirmed by diagram

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury / Mariner powerhead stud washer applications

• Mercury V6 exhaust manifold and exhaust plate assemblies

• Mercury driveshaft housing and exhaust tube assemblies

  

Typically suits:

  

• Engine models:

• Mercury 90HP 6-cylinder - serial 7208848 and up, powerhead stud washer applications

• Mercury 1150 / 115HP inline - serial 8051950 to 8061119, powerhead stud washer applications

• Mercury 140HP inline - serial 7150413 and up, powerhead stud washer applications

• Mercury V-150 - serial 0D082000 to 0G303045

• Mercury V-150 - serial 0G303046 to 0G760299

• Mercury V-150 - serial 0G760300 to 0G960499

• 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-150 DFI 2.5L - serial 0G590000 to 0G760299

• Mercury V-150 DFI 2.5L - serial 0G760300 to 0G960499

• Mercury V-150 DFI 2.5L - serial 0G960500 to 0T178499

• Mercury V-150 DFI 2.5L - serial 0T178500 to 0T800999

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

• Mercury V-150 DFI 2.5L - serial 1B227000 to 1B417701

• Mercury V-150 DFI 2.5L - serial 1B417702 and up

• Mercury V-175 - serial 4301235 to 0C100860

• Mercury V-175 - serial 8058870 and up

• Mercury V-175 - serial 0D082000 to 0G303045

• Mercury V-175 - serial 0G303046 to 0G760299

• Mercury V-175 - serial 0G760300 to 0G960499

• Mercury V-175 EFI - serial 0G303046 to 0G760299

• Mercury V-175 EFI - serial 0G760300 to 0G960499

• Mercury V-175 EFI - serial 0G960500 to 0T408999

• Mercury V-175 DFI 2.5L - serial 0T178500 to 0T800999

• Mercury V-175 DFI 2.5L - serial 0T801000 to 1B226999

• Mercury V-175 DFI 2.5L - serial 1B227000 to 1B417701

• Mercury V-200 - serial 0C100861 to 0C291519, powerhead stud washer applications

• Mercury 105 Jet / 140 Jet V6 applications where 12-20553 is specified

• Mercury Racing 200XS and related 2.5L high-performance applications where 12-20553 is specified

  

• Engine Type: Mercury / Mariner inline, V6 2-stroke, EFI, DFI / OptiMax, Jet and Racing outboard applications

• System Type: Powerhead stud washer / driveshaft housing and exhaust plate hardware

  

🔌 Function

  

The washer spreads the clamping load under the powerhead stud nut, helping secure the powerhead, exhaust plate or driveshaft housing joint without damaging the mounting surface.

  

Common signs replacement is needed:

  

• Washer missing during powerhead removal

• Washer corroded, distorted or flattened

• Powerhead stud hardware service required

• Exhaust plate or driveshaft housing service required

• Incorrect washer previously fitted

  

📦 Condition

  

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 5.25 AUD
- **Vendor:** Quicksilver
- **Tags:** Quicksilver Marine Parts | Oils Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 5.25 AUD | In stock |

## Images

- 12-20553 Mercury MerCruiser Washer | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](www.sawleysautoandmarine.com.au/products/12-20553-mercury-mercruiser-washer-genuine-quicksilver-oem-part)
> Updated: 2026-05-17