# 861839A3 Mercruiser Coupler | Genuine Used Part

🔧 Product Description

  

Genuine MerCruiser 1.7L / 2.0L Diesel Sterndrive Coupler - Part Number: 861839A3

  

A genuine used MerCruiser engine coupler for selected 1.7-litre and 2.0-litre inline four-cylinder diesel sterndrive engines.

  

The coupler bolts to the engine flywheel and transfers diesel-engine torque to the sterndrive input shaft through its splined centre. It was designed specifically for the compact MerCruiser 1.7 DTI and 2.0 EI / ES diesel families.

  

⚙️ Key Features

  

• Genuine MerCruiser diesel engine coupler

• Correct Mercury reference 861839A3

• Designed for compact inline four-cylinder diesels

• Transfers flywheel torque to the sterndrive input shaft

• Fits selected 1.7L and 2.0L MerCruiser diesel packages

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 861839A3 current Mercury service reference for the applicable diesel coupler

  

OEM / Related Numbers:

  

• 861839A3

• 861839A 3

• Flywheel-cover and coupler hardware from the 1.7L / 2.0L diesel assembly

• Related driveshaft assembly: 862772A28 on specified 1.7 DTI installations

• Coupler mounting hardware from the applicable engine serial range

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• MerCruiser 1.7L DTI diesel sterndrives

• MerCruiser 1.7 MI and 1.7 MS engines

• MerCruiser 2.0 EI and 2.0 ES diesel packages

  

Typically suits:

  

• Engine models and serial ranges:

• MerCruiser 1.7 MI 120 inline four-cylinder - serial 88109041 and up

• MerCruiser 1.7 MS 120 inline four-cylinder - serial 8810800 and up

• MerCruiser 1.7L DTI - serial 0M055000 through 0M999999

• MerCruiser 2.0 EI 115 - serial 88200000 onward in the listed ranges

• MerCruiser 2.0 EI 130

• MerCruiser 2.0 EI 150

• MerCruiser 2.0 ES 130

• MerCruiser 2.0 ES 150

• MerCruiser 2.0 ES 170

• Engines whose flywheel-housing diagram specifies coupler 861839A3

  

• HP Range: 115HP - 170HP

• Engine Type: Inline four-cylinder turbo-diesel marine engine

• Year Range: Engine and serial-number controlled

  

🔌 Function

  

The coupler transfers rotation from the diesel flywheel to the sterndrive input shaft while damping engine torsional pulses and gear-engagement shock.

  

Common signs of failure:

  

• Engine runs but drive input is lost

• Splines are stripped or heavily worn

• Rubber or damping material separates

• Knocking from the flywheel housing

• Excessive vibration under load

• Coupler overheats or produces a burning smell

• Input shaft is difficult to align

• Repeated failure caused by incorrect engine alignment

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 125.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Flywheels | Engine Flywheels & Ring Gears

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 125.00 AUD | In stock |

## Images

- 861839A3 Mercruiser Coupler | Genuine Used Part
- 861839A3 Mercruiser Coupler | Genuine Used Part
- 861839A3 Mercruiser Coupler | Genuine Used Part
- 861839A3 Mercruiser Coupler | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/861839a3-mercruiser-coupler-genuine-used-part)
> Updated: 2026-07-12