Re: [OMC-Boats] Another Wiring Question

Bill,

It's a little difficult for me to follow your description without seeing a wiring diagram. Perhaps you could sketch it out and scan it?
It would also help for you to describe the wire's COLOR and GA SIZE. But I'll take a stab at it, kinda blindly.

Normally when there is an AMMETER, the RED (BAT) 8 GA would hook up to one side (+) and the two ORANGE (8 GA) from ALTERNATOR B+ and the ORANGE (16 GA) goes thru a fuse to the BAT (input) terminal of the IGN-START Switch. (others, remember colors changed after 1969).

STEP 1) When you REMOVED the AMMETER you must COMBINE (or Tie together) all three of the above wires on an INSULATED Binding POST. DON"T USE WIRE NUTS, beyond the testing phase. An AMMETER is always wired in SERIES, so you must re-establish the circuit path when the meter is removed. Confirm that this has been accomplished.

STEP 2) When you install the VOLTMETER, connect the (+) side to the PURPLE (IGN) post of the IGNITION SWITCH and run the (-) side of the volt meter to the primary BLACK ground wire. This way the voltmeter is shutoff with the ignition key. But this approach also will reduce the accuracy of the voltmeter due to increased resistance or volt drops. A voltmeter is always wired in PARALLEL, with minimum wiring distance to the object you want to measure (at least accurately).

Alternatively, your boat should still have a correctly installed MASTER SWITCH cutoff, where you could wire the (+) volt meter lead there and just use that to turn off the meter. Use a voltmeter or test light to confirm the input and output terminals of the MASTER cutoff switch.

Lee

________________________________
From: omc-boats-bounces@... [mailto:omc-boats-bounces@...ultimate.com] On Behalf Of BLDFW
Sent: Tuesday, October 06, 2009 11:52 AM
To: omc-boats@...
Subject: [OMC-Boats] Another Wiring Question

Lee,

I've pretty much resolved the wiring issues but I do have a question regarding the connections involving my new voltmeter.

I'm using the 1968 Wiring diagram you provided earlier as it most closely represents the overall setup on my boat including the open wire connector found at the rear of the engine (none of the other diagrams I've seen show that). I'm also using the 73 vintage V8 diagram you provided as well as a 1970 color diagram Ethan (70' Explorer) provided.

Regarding the connector at the rear of the motor, this is where the three heavy gauge power wires connect from the engine harness to the forward boat harness. Because of the split vintage of the two harness's, the wires change colors at the connector to match the forward wiring harness:
   Rear--->Forward
   Brown=Orange (alternator)
   Green=Red (battery)
   Black=Black (ground)

I found a Clymer's wiring diagram that had a sections that suggested when replacing an Ammeter with a Voltmeter only, to connect the orange and the red wires together on the input side of the voltmeter. I've done that. The voltmeter now has two oranges, one from the rear and one to the fuse bank, and the red direct from the battery via the connector strip.

I now have charging but.....now the voltmeter stays powered up at all time which represents a minor drain. The voltmeter should only be powered when the key is on. It's here I'm drawing a blank on how to accomplish that. If I disconnect the red, then there is no power at the front.

I'm missing something here and drawing a blank on the resolution. Can you suggest anything?

-Bill
Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive
http://www.photobucket.com/evinrude_explorer
Received on Tuesday, 6 October 2009