Changing from an ammeter to volt meter and alternator output

[Rescue31]

Hello,
The boat is a 40 y/o 26 ft. Monark with a 165 hp inline 6 Mercruiser that I am rewiring for the fire dept. I volunteer for. In addition to rewiring the boat, I am replacing the gauges and going to a Teleflex kit. Currently the boat has an ammeter but the kit has a voltmeter. I have all the gauges installed and functioning correctly, but I have a question about the alternator output wire (orange wire) that I removed from the ammeter. It isn't used on the voltmeter and I haven't be able to find a wiring diagram that shows what to do with it after it is unhooked from the ammeter. Right now, I have capped and stowed it in the wire harness behind the instrument panel. Can anyone tell me if it must be hooked up in some manner or just leave it unhooked. The engine starts fine and there is about 12.59 VDC output to the start battery, so I am getting "some" charge from the alternator to the battery. I would prefer more output but that's the other question. Although 12.59 VDC is enough to keep the start battery charged, will it be enough to maintain the start and house batteries? I am using a BEP DVSR and a generic battery switch in the system. In the diagram I have uploaded, it shows a wire between the battery post on the alternator and battery post on the start solenoid that is removed when installing an ammeter. Should I now run a wire between those two points since I am going to a voltmeter?

Thanks for any help you might be able to give me.
Rescue31

 

[achris]

A while back I 'talked' another member through exactly this process. I even reworked a circuit diagram for him. Leave it with me and I'll see if I can find it.

Chris...

 

[achris]

I found it... Here's the instrument wiring. The new Voltmeter is in the centre of the panel. (New wires are in blue)

The changes are that you remove from the ammeter and tie back and insulate the red/white. Remove the red from the other side of the ammeter and connect it directly to the power terminal of the key-switch.
Add the white from the back of the oil pressure gauge to the voltmeter and one from the voltmeter to the water temp gauge.
Discard the current wire that runs from the power terminal of the key-switch to the ammeter.

You'll also need to change the wiring at the engine end, and I'm working that diagram now.

 

[achris]

Here's the engine diagram re-worked.

The changes here are quite simple. Cut the red/white running from the alternator (I think you said you have an orange, verify it's the same wire), insulate and tie back. Run the alternator end of that wire to the large terminal on the slave starter solenoid that also has the main lead from the battery positive on it. Job done.

Hope this helps you get it sorted out.

Chris..........

 

[Rescue31]

Thank you very much for your help. I will rewire as written and let you know how it turns out.

 

[Mccoy1981]

Need help on same kinda wiring issue but my is a 1972 Tom Sawyer with a 302 inboard/outboard motor

I have got two wire running for rear of boat an orange and red wire orange was hooked up to source on ammeter and red was on ign side with a jump coming over from there we'd help changing this over to volt ammeter with wiring

 

[Silvertip]

You just hijacked some elses thread. This is discouraged because those who are responding as well as the original poster get confused over which problem is being covered. You should always start your own post -- not tag onto an existing post. Post a diagram showing what you have so we don't have to try and figure out what you have.