just got this boat, 29 o/l baja. Big stereo, has 2 batteries special for stereo system and 2 for boat. 1 of each is mounted by each other with a perko swtch on each pair. Meaning portside has a stereo battery and a regular battery on a switch and same for other side. Please give me some insight on what the 1, 2, and all will do on this switch, and what should it be on when anchored and just listening to the radio so it wont run down my starting batteries? thank for your help.

Just guessing, '1' on each switch will be your starting battery for that motor. '2' will be the stereo battery. 'All/both' will connect both batteries together. while anchored and listening to tunes, put both switches on '2', providing they are indeed your stereo batteries, you'll have to check this out yourself.

Then switch back to '1' to start the motors. (assuming you have ran the stereo all day and pulled the batteries down too far) You can then switch to both to recharge your stereo batteries, but that may require a lot of motor run time. all depends on how far you discharged the stereo batteries.

OR replace the battery switches with battery relays/combiners. I wouldn't use battery isolators, the relays/combiners are better, though they do the exact same thing. The relays are just more effiecent. This will eleminate the screwing around of switching the switches and do the same job automatically. They only run $80 or so.