It sounds like you have tripped the circuit breaker on the main battery lead. There is a small button on the end of the breaker, and it is located within 6″ of the positive terminal.You also probably tripped the fuse on the engine. This is located under the cowling, usually on the right hand side of the engine about 2/3rds up and in the middle of the block. Start tracing those wires on that right side, and you should find a fuse there. Newer engines have the auto style fuses, older ones have the glass tubes. You probably tripped these either upon replacing the new battery and had the power on at that time. You could also have triggered them if you did not have the troller disconnected and the system is using the main cranking battery as a troller. Just reactivate everything and be sure you have it all wired up right. It could also be that you have the wiring replaced wrong after the new battery install. This could have tripped the systems and you will have to get the wiring right before moving forwards. DO NOT REMOVE THE CIRCUIT PROTECTION! It could cause a fire in the boat and damage the boat and more. Hope this helps! BCB