Your boat should be running the Merc motor. It's a two stroke. These motors do not have an oil sump like a four stroke, but get all there lubrication from oil mixed in with the fuel. You should have a separate oil reservoir beside the engine that you need to fill once in a while. The oil is automatically fed in to the motor with the fuel, so the oil tank will drop as you burn fuel. just keep an eye on it and make sure you have some spare TC-W3 oil on board.
Aaron