# 861925T3 Mercruiser 5.7L EFI GM 350 | Genuine Used Part

🔧 Product Description

  

Genuine MerCruiser EFI ECM / Engine Control Module - Part Number: 861925T3

  

A genuine Mercury MerCruiser electronic control module used in the 1999-2001 EFI GM V8 engine-control family. This ECM is listed in the MerCruiser 5.0L EFI GM 305 and 5.7L EFI GM 350 electrical-component catalogue range, with the 5.7L diagram also showing the related 861926T3 / 892798A01 ECM for 5.7L calibration. Match by exact ECM part number, engine serial number and calibration before fitting.

  

⚙️ Key Features

  

• Genuine Mercury MerCruiser ECM / engine control module

• Correct Mercury part number 861925T3

• Supersedes to Mercury 892799A01 ECM conversion kit

• Used in 1999-2001 MerCruiser EFI GM V8 electrical-control systems

• Critical EFI module requiring exact part-number and serial-number confirmation before installation

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 892799A01 → Supersedes 861925T3

• 861925T3 earlier Mercury / MerCruiser ECM reference

  

OEM / Related Numbers:

  

• 861925T3

• 892799A01

• Related 5.7L ECM reference: 861926T3

• Related 5.7L superseding ECM reference: 892798A01

• Related ECU mounting bracket reference: 861714T

• Related electrical bracket reference: 899719T01

• Earlier electrical bracket reference: 805368T

• Related relay reference: 86-865202T

• Earlier relay reference: 807057T

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• MerCruiser EFI GM V8 petrol sterndrive electrical-control systems

• MerCruiser 1999-2001 5.0L / 5.7L EFI electrical component diagrams requiring the exact ECM part number

  

Typically suits:

  

• Engine models:

• MerCruiser 5.0L EFI GM 305 V8 - 1999-2001, serial 0L331631 to 0M299999

• MerCruiser 5.7L EFI GM 350 V8 - 1999-2001, serial 0L325977 to 0M299999, when the serial-numbered electrical diagram and installed calibration specify 861925T3

• MerCruiser 5.7L EFI GM 350 V8 electrical-component family using related 861926T3 / 892798A01 5.7L ECM calibration where specified

  

• HP Range: commonly 220HP - 260HP depending on 5.0L / 5.7L EFI calibration

• Engine Type: MerCruiser GM small-block V8 petrol EFI sterndrive engine

• Year Range: 1999 - 2001

• Serial Range: 5.0L EFI GM 305 V8 serial 0L331631 to 0M299999; 5.7L EFI GM 350 V8 serial 0L325977 to 0M299999 in the matching electrical-component catalogue family

• Calibration Note: 861925T3 is associated with the 5.0L ECM reference inside the 5.7L electrical diagram family, so final fitment must be checked against the ECM label, engine serial number and required 5.0L / 5.7L calibration before installation.

  

🔌 Function

  

The ECM controls EFI engine operation by receiving input from engine sensors and commanding fuel delivery, ignition timing, idle control, diagnostic fault storage and engine-protection strategy. It is essential for correct starting, running, fuel mixture and throttle response on compatible MerCruiser EFI systems.

  

Common signs of failure:

  

• No-start with confirmed ignition, fuel pressure, injector power and ECM power supply

• No diagnostic communication

• No injector pulse or intermittent injector control

• Random stalling or shutdown after wiring and sensor checks

• Persistent EFI fault codes after verified sensor replacement

• Poor running caused by incorrect or failed ECM calibration

• Engine runs rich, lean or erratically despite correct mechanical condition

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 950.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Electronic Components | ECU CDI & Electrical Parts

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 950.00 AUD | In stock |

## Images

- 861925T3 Mercruiser 5.7L EFI GM 350 | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/861925t3-mercruiser-5-7l-efi-gm-350-genuine-used-part)
> Updated: 2026-06-29