I want to hook up a voltmeter on the engine.

[Jimmy70]

I been wanting to hook up a voltmeter to my engine but from the instructions that came with the meter is is hooked up direct to the battery. Doesn't seem logical to do this as it is a constant drain, how ever little it might be. I have a 115hp mercury, inline 6, 1977. From looking at the prints of the wiring diagram it looks like the best spot would to be hook it up to the white wire and to ground so that it will be switched off when the ignition is turned off. Does this make sense? The white wire does run to the switch box and that has be a little concerned about shorting that out, to much money for one of those. If anyone has some feed back please post. Or if there is another route to take please post that.
Jimmy

 

[mainewindrider]

Re: I want to hook up a voltmeter on the engine.

You can hook up the voltmeter anywhere. The voltage should be the same everywhere on your boat. Turning it off with all the other accessories is a good idea. Use two jumpers from your meter, one to ground and find the voltage with the other probe that is a convenient place to tie it in. Observe polarity.

 

[JustJason]

Re: I want to hook up a voltmeter on the engine.

what are you trying to check... exactly?

 

[Silvertip]

Re: I want to hook up a voltmeter on the engine.

I assume you want a permanently installed, dash-mount voltmeter. There are three wires on the meter. One for the light, one +12V and one ground. Connect the light to the light wire on any of the other gauges. Connect the +12V and ground wires to the corresponding terminals on any of the other gauges except the speedometer which isn't an electrical gauge. Therefore the backlight will be on when any of the other gauge lights are on and the voltmeter will function when the ignition key is on. You do not need to run a wire all the way back to the engine. A voltmeter is intended to measure charging system voltage.

 

[j_martin]

Re: I want to hook up a voltmeter on the engine.

The white wire on yer machine is switched battery voltage. Shorting it out will burn the wire and kill the engine, but wouldn't hurt the switchbox.

If you hook up the light to the lighting circuit to the other gauges, and + to the white wire for the tach, and - to the black wire, you should be good to go. The tach signal wire is brown.

hope it helps
John

 

[Jimmy70]

Re: I want to hook up a voltmeter on the engine.

John that was my thinking also once I crawled under the dash and gave it a good look over. Thanks to all of you for your feed back on this.
Jimmy