Brucato ACU Self-Help Center, Mercury ECUs

Mike Hill
5 days ago
3 min read

Welcome to the Brucato ACU Mercury ECU Replacement Self-Help section from Buckshot Racing #77.

Since Brucato decided to close down rather than sell their operations, we have compiled the most important technical documents into a single, easy-to-use hub.

All files are free PDF downloads. Each document includes clear instructions, diagrams where available, and practical advice for Mercury EFI, XRi, ROS, and Pro Max outboards (150 HP, 175 HP, 200 HP, XRi, 225 Pro Max, 260 EFI, 280 ROS, 2.4 Bridgeport, etc.).

Use the categories below to find exactly what you need. Every PDF is named for quick understanding and optimized to provide helpful access.

1. Installation & Setup

These guides walk you through swapping your old Mercury ECU for the Brucato ACU. The ACU is plug-and-play in most applications.

Brucato ACU Installation Instructions: Step-by-step guide to physically install the ACU, including bracket reuse, wiring, and MAP sensor hose connection.

Brucato ACU Quick Start Guide: Short, one-page checklist for first-time users – perfect for getting the motor running quickly after installation.

2. Tuning & Adjustment

Learn how to fine-tune fuel delivery, rev limiters, and EGTs using the optional interface cable or adjustment pots on the ACU.

Brucato ACU Fuel Tuning Guide: How to use the management software or adjustment screws to modify fuel at different RPM and vacuum levels for optimal performance and economy.

Flash, Brucato ACU Tunes, Mercury ECU

$20.00

Buy Now

Brucato ACU Rev Limiter and EGT Tuning: Explains fuel-based rev limiting, safe exhaust gas temperature (EGT) monitoring, and how to avoid lean conditions under load.

3. Spark Plugs & Supporting Parts

Correct spark plugs are critical – the Brucato ACU is more sensitive to RFI than legacy 2-stroke stock Mercury ECUs.

NGK Spark Plugs for Mercury V6 with Brucato ACU Recommended NGK resistor plugs, proper gap (0.035"), and why non-resistor plugs can cause issues. Includes application chart for 150–300 hp motors.

NGK Spark Plugs for Mercury V6 w/ Brucato ACU

From$30.00

Buy Now

4. Troubleshooting

Common Mercury EFI symptoms and fixes for rough idle, bogging, hard starting, and other issues.

Brucato ACU Common Troubleshooting Guide: Covers bogs on acceleration, won’t plane, runs rich/lean, rough idle, and sensor-related problems. Includes checks for TPS, MAP hose, fuel pressure, injectors, and more.

5. General Information & Safety

Important notes to keep your Mercury outboard motor safe and reliable on pump gas or race fuel.

Brucato ACU Safety and Best Practices Fuel type recommendations (pump gas vs race fuel), ethanol considerations, break-in procedures, monitoring tips, and general operating guidelines.

6. Bonus Files & Reference Materials

These additional files provide extra technical details, diagrams, and quick references that many users find helpful.

Brucato ACU Software Management Instructions: Full guide for using the Brucato software interface, loading files, and basic management of the ACU.

Brucato ACU Cold Start Enrichment" Explains how the ACU handles cold-start fuel enrichment (adds pulse width instead of buzzing injectors).

Brucato ACU TPS / TPI Adjustment: Step-by-step instructions for adjusting the Throttle Position Sensor (TPS) or Throttle Position Indicator for proper idle and part-throttle response.

Brucato ACU FCR-4 Wiring Pinout Diagram: Visual reference showing the FCR-4 connector pin configuration and wiring harness details.

Brucato ACU Applications Reference: Quick visual chart showing common Brucato ACU applications and compatible Mercury EFI outboards.

Brucato Test Data Example: Sample dyno or test data sheet for reference when tuning.

7. Fuel Injector Clean, Flow, and Rebuild Service

Buckshot Racing #77 provides a comprehensive injector service and replacement parts for Mercury Injectors

Fuel / Air Injector Clean & Flow Service

From$25.00

Buy Now

How to Use This Self-Help Section

Click any Download link above.
Save the PDF to your phone or computer for quick reference at the boat ramp or shop.
Most documents include diagrams and bullet-point steps written for everyday users.
Need a custom fuel curve or help with a specific motor? Visit our Brucato ECU Fuel Curve Tunes page.

Important Note: Always disconnect the battery before working on the ECU. Use resistor spark plugs only. Monitor EGTs and spark plug color when tuning. If you are unsure about any procedure, consult a qualified marine technician.

This self-help center will continue to grow as we add more guides. Bookmark this page and check back often.

Last updated: April 2026 Buckshot Racing – Keeping your Mercury Promax and EFI motors running strong.