questions on wiring on/for F75TLRB

[<Larry>]

Hi, I've got a few questions regarding the associated wiring on my '03 75HP 4-stroke. If this post seems a bit long-winded or too noob-ish I apologize up front.

The motor is mounted on a Sylvan along with a model 703 remote control, with power tilt/trim and choke lever. The boat currently only has a speedometer w/pitot tube and fuel gauge, and the connections between the gauges and the remote control is via a harness with a Smokercraft (Sylvan -&gt; division of Smokercraft) part #.

I want to add at the least a tach and a trim/tilt gauge, so I'm trying to decipher the existing wiring. I'm not compelled to replace the 2 guages there already but I'm not against doing so either.

Coming out of the 703 control there are 3 cables with bullet connectors. The first cable has the red, black (ground), yellow (switched power) and dark green wire. I assume this dark green wire is for the tach? I'm assuming the red is unswitched power but haven't confirmed it.

The other 2 cables each have a red, light green, and light blue (purple?) cable, and 2 cables of each color are spliced together, so there are 3 more free bullet connectors. What is the purpose of each these wires?

Also, looking at the starboard side of the engine a few inches from the fuses, there are 2 connectors that I'm trying to identify.

The first one is a 4-pin female connector with 2 wires; 1 dark pink w/black stripe, the other ligher pink w/white stripe. It appears that light pink wire runs to, or near, the oil pressure switch on the upper port side and the darker pink wire runs to or near the TPS on the lower port side.

The 2nd connector is a male connector with a black and a pink wire and also a grey wire which is approx. 2" long with its other end terminated by a bullet connector. The black and pink wires run into a plastic jacket which itself appears to run to, or at least near, the PTT unit mounted at the front of the motor's mounting assembly.

What is the function of these 2 connectors, and will I need some kind of standard auxilliary harness that connects to them and which runs to the 703 and/or the gauges directly?

I haven't decided on exactly which gauge type I'm going to use so I can be flexible if needed, if there's a recommendation of a particular type/style I'd like to hear it as well.

I do have the recommended (F100X) service manual, but if the info I'm looking for is in there I've completely missed it.

Thanks for any help.

-- Larry

[<boats.net>]

I reconmend using Yamaha 1 Gauge rigging kit (6YR-W0035-E0-00), it has a multifunction tach with trim gauge, hour meter,low oil pressure light and overheat light and all the wiring harness needed.
It has the harness that connects it to the engine, those two connectors you found at engine (Trim sender and low oil pressure leads) and the harness to connect to 703 control box ( the Red,yellow, Green,and Black wires). The Red, Green and Blue leads on control box are for a auxillarly trim switch connection.
As far the other gauge wiring in boat there is some different's in color.

Boat: Yamaha:
12 volts Red Red
12 volts with key on Purple Yellow
Tach sender Gray Green
Light's (gauge's) Blue Blue
Ground Black Black

[<Larry>]

Would it be just as easy for me to order the multifunction tach/speedo kit (6YR-W0035-F0-00)and replace the existing speedo and fuel gauges so that everything matches up?

The only specfic thing I could think of by going that route would be what I would need for a connector (or connectors) for the pink & black wires coming from the fuel level sensor, I've never seen the back of the speedo as part of that kit.

You're right about color mismatches between the Yamaha and Smokercraft harnesses, I don't remember a grey wire off the top of my head, but the Smokercraft switched-power wire IS purple.

Thanks for your help so far.

[rgyr]

I also have a question about the wiring for Yamaha Multi-Function Guage (tach/tilt/temp/oil). I had 2001 F40 installed in the fall of 2000 along with a new Multi-Function Guage.

I was checking the boat out this week and noted that all guage readouts appear to be functioning properly. However, I do not think the display lighting is working. I use my small boat very seldom, have never been out in it after dark, and just realized I had never seen the gauge display lighted.

I have a pull out light switch (off/1 on/1 and 2 on) for stern all-around light and bow red/green running light. Looking under the small console I see a blue wire apparently coming down from the gauge wire bundle and this is connected to a lead wire connected to the 1 on (with stern light) terminal on the light switch. The switch is connected by red wire to the +/red terminal on the battery. If blue conductor is supposed to be switched power (+) lead to gauge light, how is the gauge light grounded? Is it through its connections to the engine wiring? Is the gauge supposed to be lit when the engine key is on and the light switch is turned on? Could it be so faintly lit that I can't see it during the bright daylight (I tried to shade the face of the gauge when I was looking)?

Boats.net offered some good information on these gauges in the reply above and I would love to get a reply from him or another knowledgeable poster. This is my first time to this board.

Thanks