90hp ELPTO wiring information request

[Pittpontoon]

I bought an 04 Bentley Cruise 200 (first boat) at the end of the season last year and got to use it for a few weeks until we put it in storage. This year I wanted to install a new fish finder, and when I dug into the dash it was a disaster. Melted wires everywhere.

Apparently the previous owner had hooked up a battery backwards and must've smoked a good portion on the engine wiring harness (I found some hacked together cables put on as a bandaid). I'm trying to replace any bad sections, run new ground wires, replace corroded battery cables, and generally "make things right."

I searched for a couple hours but couldn't find any service manual for my motor ('03 Mercury 90hp 2-stroke ELPTO).

I've sorted out most of it, but the temp alarm buzzer doesn't appear to work (no tone when key is turned to on prior to starting), and there's still some fried cables that I don't believe are used but I want to verify. I also want to better understand the motor side wiring (like why are the tan wire and brown/white wire broken out with plugs and plugged together??? The joys of being a 4-5th owner!) so a service manual would be great. If anyone can help I would really appreciate it! I'm looking forward to finally getting in the water once I finish this project. I want the temp alarm to work, and may want to add a temp gauge in the future as well (it appears that there's a sending unit installed in the motor).

 

[ondarvr]

It's not that easy to do a search here.

http://forums.iboats.com/forum/engi.../606521-wiring-diagram-for-2002-mercury-90-hp

 

[Pittpontoon]

Thanks, ondarvr. That will be useful for future projects I'm sure. I appreciate the help.

Unfortunately I don't see anything on that diagram for the brown/white or tan wires coming off of the engine harness. I would post a picture, but I get an error saying that I'm unable to add attachments.

 

[Pittpontoon]

I just found a post that has a picture of the brown/white and tan wires. I basically have the same question as that guy:

http://forums.iboats.com/forum/engi...altwater-series-model-90exlpto-wiring-harness

 

[ondarvr]

I have an 05' 90 ELPTO, but it has a tiller, so I don't think the harness is the same, I'll go out and look.

 

[dandreye]

Pittpontoon:

I have one of those engines made in 2000 or 2001. In the unlikely case you still need help with this:

(​BRN/WHT below is brown with white stripe; TAN/BLU below is tan with light blue stripe)

- BRN/WHT is trim sender circuit that should connect to the only wire (besides GND) coming from/to your outboard's PTT. The other end of this wire in the wiring harness should connect to the trim gauge on your dashboard if you have one installed at all: it displays your outboard's current position i.e. the angle it's trimmed/tilted to.

- TAN circuit is somewhat more complex: it's shown in remote control/wiring harness electric diagram but it doesn't show up anywhere in the outboard's electric diagram. According to the intl marine wire colour coding convention it's supposed to be a temperature related circuit, and the temperature implied could be cylinder block temperature or cooling water temperature. Afaik in standard/factory configuration our outboard has no temperature *sender* (its design allows installing one though) - it only has cylinder block overheat warning *switch*, which shares TAN/BLU circuit (that goes to the alarm buzz in remote control) with the low oil warning switch. Those switches are normally open and just ground their circuit when closed. So I guess tan wire is just an auxiliary one that you can use to your liking, e.g. to terminate your low oil circuit elsewhere than at the alarm buzz in remote control (potentially dangerous though, in case it's not as annoying as that beeping buzz is) or to install cylinder block or cooling water temperature *sender* and terminate its circuit on a temp gauge on your dashboard thereby getting accurate temperature readings well before overheating, or for any other purpose (I know some guys who use such idle wires to power their stern light that they install right into the hood). I'm considering using it to terminate my low oil warning circuit on a special gauge that flashes red + a dedicated alarm buzz that's not as disturbing as the standard one in remote control is: once it beeps first I know exactly how much oil is still left there and need no further warnings on my entire way back home.

Here's Commander 2000 remote control/wiring harness electric diagram assuming that's the one you have:
https://s2.postimg.org/41j5rx17d/Capture.png

Having brown and tan plugged into each other as in your case sounds like someone's mistake, albeit most likely w/o any damage caused.


HTH.


P.S. The buzz shouldn't beep at all on these outboards when you turn ignition on, or in any other key position. It should only (in standard/factory configuration):

- beep intermittently upon low oil, i.e. oil level dropping below some predefined level in your engine oil tank (I think something like 1/4 - 1/3 of it)

- beep continuously upon cylinder block overheating