I just bought the boat. I got the battery replaced and when I put the black on - and red on + with the little green and black wires, I have no accessories, nothing ! (radio, rpm, speed, lights ...).
This boat has a battery rotary switch on the side of the rear storage area, ensure it's switched on. Next if you follow the red lead from this switch, there is an inline 3 amp fuse, check that it's good. Also check the main fuses in the box right behind the driver. Ensure the battery is charged by checking with a multimeter also. Good Luck.