Please read and understand these instructions.

The PCU comes preprogrammed with a preliminary fuel curve for your application. Contact Brucato, Inc. with any questions you may have at 919-718-0249.

The preliminary fuel curve may be adjusted by the user with the array of potentiometers contained in the PCU.

The overall fuel delivery may be adjusted with the optional steamwheel.

Acceleration Compensation feature adds extra fuel delivery when throttle movement is detected for optimum acceleration.

The programmed fuel curve may be customized with the optional interface cable. This allows manipulation of fuel delivery at different vacuum/RPM levels. Additionally, the rev limiter can be adjusted.

With the optional extension harness, the PCU can be mounted next to the driver for easy adjustment.


Connect ECU harness, vacuum line, and steamwheel (if used) to the PCU.

Mount the PCU, securely in the cockpit within reach of the driver utilizing the extension harness. This allows for easy adjustment and will extend the life of your PCU by avoiding engine heat and vibration.



Tools Needed:

Small Phillips screwdriver
Exhaust gas pyrometer recommended


After removing the cover of the PCU, you will see several knobs which have an adjustment range of -15% counterclockwise and +15% clockwise.

The pointer location of the Phillips head is denoted by the slot with half circles on either side. (Shown straight up in the first image below 0%).

Each of the graduations on the body of the potentiometer represents approximately 4% adjustment, however, adjustments as small as 1% may be made. Negative adjustments are counterclockwise and positive adjustments are clockwise, as shown below.


Knob marked "Main" controls entire fuel delivery.

Accel Comp Sensitivity adjusts the minimum amount of throttle movement required to activate Accel Comp function.

Accel Comp Volume controls volume of extra fuel metered during acceleration.

Part Throttle adjusts fuel delivery +/-15% at less than full throttle in the RPM range of 1,800 through 7,500 with no affect at wide open throttle.

Idle - adjusts fuel delivery +/- 15% at less than full throttle in the RPM rage of 0 through 1,800 with no affect at wide open throttle.

Group 2 and Group 3

Injectors are grouped in pairs. Group 1 controls cylinders 1 and 2, Group 2 controls cylinders 3 and 4, and Group 3 controls cylinders 5 and 6. Groups 2 and 3 can be adjusted separately from the Main adjustments +/-15%.

RPM Knobs

The programmed fuel curve can be altered at the various RPM levels +/-15%.

Tuning Your PCU

Although it is simple to tune the PCU, thorough knowledge of engine tuning and the means to monitor the fuel mixture of your engine will be required. If you are unsure of your ability to tune the PCU, contact a professional for assistance.

A previous benchmark exhaust temperature reading from your engine at each RPM band will be very helpful to you when tuning the PCU.

Tuning of the PCU is meant to begin on the rich side of the fuel curve, and then carefully worked back to the optimum fuel mixture.

After mounting and connecting your PCU and steamwheel, with boat and motor in the water, start and idle the engine. Set the steamwheel at +10% while watching the pyrometer, run the boat up to full throttle, making note of any RPM range that brings the pyrometer reading up to normal.

In increments of 4% or less, adjust the steamwheel lean, repeating the above instructions until some of the RPM band are at the correct fuel mixture. At this point, you will have identified which RPM bands need adjustment.

The fuel curve can be adjusted precisely by using the knobs, either adjusting rich or lean as needed at specific RPM points.

EXAMPLE: The exhaust gas temperature approaches optimum reading only in the 5,000 to 6,000 RPM range, and the rest of the RPM range appears rich. The method for tuning is to add additional fuel in the 5,000 to 6,000 RPM range via the knob adjustments, and then remove fuel overall with either the Main adjustment knob or steamwheel. Continue this method using smaller values until a satisfactory fuel curve is achieved.

At this time, you will have a 95% finished fuel curve. Further tuning will involve concentrating on smaller adjustment increments on certain RPM ranges, at wide-open throttle, utilizing the methods previously discussed.

NOTE: Turning the steamwheel knob fully counter clockwise through the negative range will reset the adjustment to 0%.

NOTE: To load the engine down at various RPM levels long enough to get sufficient data for adjustment, it may be necessary to use a large pitch propeller and negative trim.

Acceleration Comp It may be necessary to experiment with different settings of volume and sensitivity to achieve crisp acceleration from idle.

Group 2 and Group 3 Adjustments After tuning the fuel curve as we did above, plug readings should be taken to determine if any group of injectors requires fuel compensation.


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