Merc 4.3 Does it have a internally regulated Alternator

[timothy2222]

I am hooking up a dual battery system with a 4 way switch 1/2/1+2/off.
Do I have to connect up the field switch with my motor?

If I dont will it be safe to switch batterys when the engine is running?

My motor is a MCM 175 1989 mercruiser 4.3

My alternator has 3 wires comming out of it.

 

[97proline2810]

Re: Merc 4.3 Does it have a internally regulated Alternator

Never a good idea to switch batteries when the engine is running unless you absolutely have to. If you don't have a separate regulator, than it must be internally regulated. You don't need a field wire, only the large wire that connects to your solenoid

 

[Don S]

Re: Merc 4.3 Does it have a internally regulated Alternator

If you bought a new battery switch, they are all make before break contacts when switching from 1 all and 2. Which means you can go between 1,2 and all, but DO NOT shut off with the engine running. That will take out your alternator diodes.
You so nor need the FD terminals, you have an internally regulated alternator on your engine, unless you installed one of those high output alternators with a separate regulator.