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

🚤 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

🔄 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

📦 Condition

• Genuine used part
• Removed from running engine where applicable
• In good working condition unless otherwise stated