can you check boost if motors are not under load or does the boat have to be in the water.

Under load.

In neutral, your throttles barely need to be opened to bring engines to redline. Throttles are the airflow / power regulator of your engine.

A said, must be under load. Even the amount of load will affect boost pressure. I installed a 1" larger drive spacer on my Pantera. The prop bit so much more that boost presure went up 1.5#'s.

thank you for your help so in the water we go.