What is the proper position for my Perko battery switch on 271.

1, 2 or all.
Will I charge both batteries and only draw from one if the switch is on 1 or 2.

I would think it would be best to have one battery on reserve.

First rule of questions, there is no dumb question.

I would leave them on both as I usally do.

Is your boat single engine? If your switch is wired correctly if your on switch position 1 then #1 battery is connected to the engine, if it is switch position 2 then #2 battery is connected to the engine, all is both batteries connected in parallel to the engine. I would always run in all unless you have a big stereo you like to run at anchor or when beached, if that is the case hook your stereo system to one battery. That way you can select that battery on the switch and drain that battery with the stereo but still have a battery to start the engine with.

it is a single 502 with factory wiring and a normal stereo that doesn't get used much.

So, if it is in 1 or 2, is the engine charging only that battery?

^^^^^Correct.

Thanx for the info guys,
Sounds like "all" is the way to go

I run around on both and then switch to 1 when I'm anchored swimming with radio on.

x2

X3 don't make the mistake of running both batteries down while anchored and blasting tunes on the stereo.

By doing that , you are using #2 as your starting battery? I do just the opposite. Really should not matter, I just always thought of battery #1 as the main starting battery.On my 330, #1 was the stronger cranking battery.