PDA

View Full Version : Wiring Gauges For mercury 115 Inline 6



Bill85
05-01-2006, 07:55 PM
Just wondering if anyone has the wiring diagram for the mercury inline 6
i just got the boat and none of the gauges are hooked up. i have a tach, fuel gauge, and speedo im quite sure if i need any more gauges.

ShorePounder
05-03-2006, 06:00 PM
Hi Bill, Welcome to Scream and Fly!

As to your question. It's been awhile since I played with an inline so I had to go back and dig up my diagrams. The tach signal wire is the brown wire in the harness. 12v+ is the white wire and GND is the black.

The white wire is the 12V source when the key is on. You can use it to power any gauges that need power, but for anything else, I'd recommend using the white wire to fire a relay that switches a main bus 12V wire from the battery. In discussions with Jeff G, and some others who are inline savvy it came out that the old inline switchbox is sensitive to low voltage situations. It likes a fully charged battery and a good strong 12V on the white wire and doesn't like to share. :) A few gauges and a relay coil won't put much drain on the white wire and the switchbox will be happy. You try to run a fuel pump, radio, rack of gauge lights, etc and you'll be pushing your luck.

Have you given any thought to a water pressure gauge and maybe a water temp gauge? Both are great to have.

Bill85
05-03-2006, 09:24 PM
I have a speedo and fuel gauge, a water pressure gauge and a volt meter

ShorePounder
05-03-2006, 10:03 PM
that should be fine

sho305
06-29-2006, 11:10 AM
I think the non-distributor ignition is more sensitive to voltage drop, though I would not recommend using the hot wire for much either (and its not that big a wire). I think mine runs the tach and maybe the fuel gauge (? it does not work and I never looked), everything else is on the battery itself like the lights/horn/bilge pump/etc. I have run it not charging when I had a bad rectifier until the motor started to cut out at high rpm...when I got back to the dock the starter would not even click it was so dead. It ran fine up to then, but I have the old '73 distributor and thunderbolt ignition. Got the new regulator on it a couple weekends later and then it overcharges the battery all the time, but thats the way it is. Maybe it was not smart to do that, but I needed to run. However the second weekend I hooked a jumper to it and I could run it for as long as I needed without it going dead, then I charged it back up.

Most boats I have worked on were wired that way, and the hull had extra wiring for all the accessories that was heavier wire direct to the battery. Some have a switch or relay to fire up the gas gauge and other things you want on with the key.

hsbob
06-29-2006, 04:51 PM
look here
http://www.teleflexmarine.com/cgi-bin/frameset2.cgi?site=gauges&type=int&link2=1047


i has wiring diagrams for guages.