re: Hooking up a perko switch in my boat...need advice

Only problem with that wire diagram is that the bilge pump should always be hot. It should always over ride any cut off switch and should be hook direct to power with a fuse in line if you have a auto bilge pump.

A perko battery switch has battery 1, battery 2, both battery 1&2 and off.

Battery 1 should just feed the motor.

Battery 2 should just fed house power.

Battery 1 & 2 ties everything together.

Off cuts all power to everything but a auto bilge pump that should be hook direct to the hot side incoming of battery 1&2.

OP. To save you time in the long run, use only tin wire and connections. You can order that off ebay a lot cheaper then buying it at a boat shop.