Holley pro-jection 2D Installation And Troubleshooting Manual - page 23
NOTE: Many engines require a richer fuel mixture at idle. Therefore it may not be possible to maintain the fuel mixture at a
stoichiometric level while maintaining the engine at a smooth idle. Adjust the idle fuel delivery that best meets your
engine’s requirements.
NOTE: If you are unable to adjust the IDLE adjustment knob to achieve a proper idle, it may be necessary to once again adjust
the mechanical idle adjustment screw. This is located on the driver’s side front of the throttle body. Adjust this to a
higher setting, as described on Page 19 of this manual. If you change the setting of the idle adjustment screw, it will be
necessary to once again adjust the TPS to the proper idle setting as described on Page 19 of this manual. Once the
TPS and idle have been adjusted, it will also be necessary to adjust the MAIN adjustment knob as described on page
20.
2. Now return to SETTING THE THROTTLE POSITION SENSOR (TPS) and follow the steps outlined to adjust the TPS again.
Once the TPS has been reset return to TUNING THE MAIN and adjust again. Then return to step one of this section and
tune the idle again.
18.3 Tuning the ACCEL
The ACCEL adjustment knob controls the amount of fuel that is added to the engine when accelerating. Adjustments made here
allow for a quick, crisp response during acceleration.
1. Shift the transmission into gear and slowly accelerate the boat to plane.
2. Quickly open the throttle and note the performance of the engine. If the engine bogs (falls flat) and black smoke comes out
of the exhaust, the ACCEL adjustment is set too high. If the engine bogs and no black smoke comes out of the exhaust, the
ACCEL adjustment is set too low.
3. Adjust the ACCEL adjustment knob accordingly and continue performing acceleration tests you achieve a quick, crisp
response during acceleration and no black smoke comes from the exhaust.
18.4 Tuning the High RPM
The HIGH RPM adjustment knob changes the fuel delivery to the engine at engine speeds over 3000 rpm.
NOTE: To properly set the HIGH RPM setting, it will be necessary to operate your engine at a steady speed while determining
the proper fuel delivery.
1. Begin to smoothly accelerate the boat until the engine speed is above 3000 RPM. Now quickly press the accelerator and
perform a hard acceleration. Note the performance of the engine.
2. Bring the boat to a complete stop. Increase or decrease the amount of fuel delivered during high engine speeds by turning
the HIGH RPM adjustment knob either clockwise or counter-clockwise. If your vehicle is equipped with a Rich / Lean
indicator, adjust the HIGH RPM adjustment knob until the meter indicates a slightly rich fuel mixture at high engine speeds.
3. Adjust the HIGH RPM adjustment knob accordingly and continue performing acceleration tests until you achieve a quick,
crisp response during acceleration.
18.5 Tuning the Choke
The CHOKE adjustment knob controls the fuel delivery to the engine during a cold start. Adjustment to the CHOKE should be
made after the engine has cooled down completely.
1. After the engine has cooled down completely (Holley recommends allowing the engine to sit overnight), start the engine.
2. Immediately after starting the engine, shift the transmission into gear and accelerate slowly.
3. Turn the CHOKE adjustment knob to achieve a clean drive-away from a cold start. Several cold starts will be necessary to
zero in on the proper CHOKE setting.