The watercraft have worked with no problem until yeasterday, the engine cut off in the middel of the ocean and it was not possible to read the key, because the screen truned off. It would only read the key if the start botton was pressed, and then the screen turn off again. After some time it started again and shut off again just before the dock, and havent started since, we have bought a new batteri to put in, but the problem reapperd. What could the source of the problem be?