if you look at the instructions, the warning is to NOT run the boat at planning speeds with the seacock OPEN and the genset OFF. a running genset while under way would tend to be normal operating procedure. others will chime in.
i assume by "AC" you mean air conditioner. if so, the genset actually needs to operate under load, so that is what would be required (or other draw equipment). if by "AC" you mean the shore power switch on the panel, then your genset would not be providing power to the grid and you would then be running it without a load.
good luck, ron
