Technical Resources | Brucato ACU Technical Information

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Brucato ACU Technical Information and FAQs

T.P.S or T.P.I. Adjustment

The Brucato ACU does not use your factory TPS, so no adjustment is ever needed.
As a matter of fact, you don’t even need to have a TPS. One less thing to worry about.
The Brucato ACU uses MAP sensor readings (the yellow hose) along with engine RPM to determine the theoretical throttle position. On our older ACU’s with the grey cast housing, or with the Brucato PCU, it’s recommended that you disconnect the TPS to avoid any problems. This is not necessary with the new black billet ACU’s, as they are ready to go even with the TPS plugged in.
Click HERE to download T.P.S. or T.P.I. Adjustment pdf
Adobe Reader is required for download.

Cold Start Enrichment

The Brucato ACU has cold Start enrichment capability, but it works differently than the Mercury
ECU.
The Mercury ECU will buzz the injectors, even without engine RPM. The Brucato ACU does not buzz the injectors, but instead, it increases the injector pulse width by 2ms to add extra fuel.
If your motor has the yellow/red stripe wire from the engine ECU harness connected to the starter solenoid, you have nothing to worry about, as the enrichment function happens every time you crank your motor.
If your yellow/red stripe wire from the engine’s ECU harness is connected to the yellow/black stripe wire from the key switch harness, then your key switch will have a push-to-choke function.
When using the ACU, you will need to push the key in WHILE cranking the motor. Just treat it like it was a choke on a carbureted motor.
Unlike the Mercury ECU, it is imperative that the engine’s air temperature sensor is functioning correctly. This sensor can be OHM tested using a digital multi-meter.
Click to download Brucato ACU Cold Start Enrichment pdf
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Brucato Spark Plug Requirements

ACU Quick Start Guide: Spark Plug Requirements

Spark Plugs: You MUST only use resistor spark plugs with the Brucato ACU. This may or may not be the Factory Mercury recommended spark plug that is in your motor now.

Here are our recommendations for your motor. All recommendations are NGK spark plugs. Please do not substitute any other brand.

All Stock Mercury/Mariner 150, 175, 200, 220 XRI motors up to 1999; BR8HS* or BUZ8H**

All Stock Mercury/Mariner 150, 200, 225 ProMax/Super Magnum; BR8HS* or BUZ8H**

Year 2000-2001 Mercury 150, 175, 200 BPZ8H

Mercury 240 Sport Jet BPZ8H

Mercury 2.4 Bridgeport Offshore BR9HS*

Mercury/Mariner 260, 280 with 260 electronics BR9HS* or BUZHW***

Mercury/Mariner 300 Drag BR9HS* or BUZHW***

Notes:

*This is a ground strap electrode type spark plug. This should be gapped @ .035”. Be sure there is an “R” in the part number. This is what designates this as a resistor plug. You can also use a part number with a “-10” suffix, such as BR8HS-10 or BR9HS-10. This signifies that they are pre-gapped at .040” (1mm). You will still need to gap them @ .035”.

**BUZ8H is an inductive resistor surface gap spark plug. This is a more expensive option to the BR8HS. The “Z” in the part number is what designates this as an inductive resistor plug. It MUST have the “Z” in the number. Do not use BU8H !

***BUZHW is an inductive resistor surface gap spark plug. This is a more expensive option to the BR9HS. The “Z” in the part number is what designates this as an inductive resistor plug. It MUST Have the “Z” in the number. DO NOT USE BUHW !

Click HERE to Download a copy of Spark Plug Requirements for the Brucato ACU

Adobe Reader is required for download.

Brucato ACU Motor Applications