Yamaha 703 control box and Rubik's cube - stowing cables

[99yam40]

Enjoy it ,
you will get back to the heat in time for the real hot months will you not?
Hope you are able to catch some nice fish while down there

[exeter27]

***, I'm pretty good with schematics - but Yamaha in its wisdom has decided to leave out some key information. That would be ok if they were consistent with colors. But, I've figured out enough so that I think I can piece this together - with some help from the folks on this forum.

My tach has the following wires:

warning lamps: oil and overheat

green with brown dot - overheat ground

red with brown dot - oil ground

yellow with brown dot - common 12v positive for these lamps

backlight lampblue - backlight 12 positive

black - backlight ground

Meter control

Yellow - unknown

Black - unknown, but assumed ground

Green - unknown

I need help identifying the meter control wires. See red text above.

Then I need help on the engine end. I need to know which connectors to bring forward to the tachometer. I see one one connector that has two pink/black, 1 pink, and 1 pink/white wires. That is a female connector. I then have another 4 position connector (male) that has black and pink wires - and 2 empty positions. Finally, under the plastic cover (not the CDI piece), I see two bullet connectors - one yellow and one green. My hunch is that these need to connect to the yellow and green wires on the tachometer.

So, what connectors on my 2004 F60 are needed to be brought forward, what color are they, and what are the type of connectors (nylon 2 position, nylon 4 position, bullet, etc.)?


Thanks in advance! I'm almost there!!!!! I want to get this running in the next day or so!

[boscoe99]

Yellow is key on 12 volt positive.
Black is ground.
Green is the tachometer reference signal.

These wire colors are in the main ten pin harness and do not change color across and through the fused gauge harness that connects to the tachometer, trim gauge and any other gauges.

The 68F trim and oil harness carries all other necessary information from the motor to the gauges. You do not need to be concerned with specific wire colors as it is all plug and play. Connectors are gendered so that a misconnection is all but impossible.

The needed adapter harness will take information from both of the trim and oil connectors and consolidate them into one connector attached to the tachometer. The single pink wire from the tachometer jumpers to the trim gauge. It carries trim sender information.

Of the many wires to the two engine mounted connectors, only three are used in your particular application. One is the low oil pressure ground, one is the over temperature ground and one is the trim sender reference information.

[exeter27]

Ok, I now know all wires at the tach - no unknowns there.

What I need is the cables on the engine that provide oil pressure ground, overheat ground, and trim send. Unfortunately my cables don't match the engine - so I'm going to need to improvise. That's why I need specific cables at the engine.

boscoe99, thanks so far for your information. I just need those 3 specific connectors. Like I said I have one 4 position connector with 2 pink/black, 1 pink/white and one pink that could be the right connector...

[exeter27]

More staring at the schematics in the service manual (in this case the 50 manual - which has more stuff) - has yielded more information.

The unused (and plugged) bullet connectors behind the plastic cover on the port side of the engine are for an hour meter. I don't have one - so I won't use them. The tach is still a work in progress. Nowhere does Yamaha specify which wires at the engine end are the oil pressure and overheat cables. I believe them to be the pink white and pink - but cannot confirm. When I put the key into the 'on' position - neither the oil nor the overheat lights come on. Can someone confirm if the oil light comes on at 'on' position and the key not yet moved to 'crank' position? I would think it would come on...but it didn't.

I post all this on the chance that someone runs into an issue in the future where the tachometer and the engine are 'incompatible' - and then the plug/play goes out the window...

Tomorrow I may just fire this up and see what happens.

[exeter27]

Progress - but critical functions still needed

I made good progress today. I fired up the engine and it worked great! Also, my tach was working properly - so that's all good stuff! However, I am not getting anything from my warning devices.

I verified that the oil pressure switch registers continuity when the engine was running. That shows that I had pressure and that the switch was functioning as designed. However, I went so far as to remove the lead from the oil pressure sensor - theoretically guaranteeing that the oil sensor light should go on - and it didn't.

I have not verified operation of the thermoswitch. That one shows continuity if the temp goes too high - and my cooling system is work fine. I'll need to take that out and test per the service manual. My hunch is that it is fine.

I have tested the lights on the meter and they illuminate when I ground the two different leads for oil and temp. So, I know they are good.

I did check the bullet connector (pink) that goes into the CDI harness and it showed connectivity from the oil sensor to the bullet connector. Once it goes into the CDI - it's anyone's guess what happens in there. I can't (yet) find where Yamaha specifies how this signal is propagated back out of the CDI box.

I will continue to pursue this and nail it down. The fact that I didn't hear my horn go off in the control box concerns me as I'd expect that the disconnected oil sensor should have set it off. So, back up front to the control box. Funny, this started as a thread discussing the challenge of fitting the cables in the control box. It's grown well beyond that!

Hopefully someone is entertained by all this!

[exeter27]

I know this is a necro-bump, but I always try to follow up on my posts with a solution. And today I finally decided to nail this issue down. The outboard has been running great in the intervening years - I just didn't like having an non-operational oil warning light. So I really dug in on this one.

In a nutshell, the service manual schematics and oil pressure switch test procedure show that the oil pressure switch is 'normal open'. In other words, no pressure means that the switch is open - and it closes when (oil) pressure is applied. Well, my switch shows continuity (switch closed) when no pressure - and no continuity when there was pressure. So either the manual is incorrect or my switch is bad. Even saying it is 'bad' is a misnomer, as it works - just opposite of what the manual suggests. That either means my oil pressure switch was swapped with an incorrect one or the manual is incorrect. Research of markings on my switch suggest it is the correct switch. I could have gone to a Yamaha dealer with my multi-meter and measured one of there's for a definitive answer - but I went rogue.

Basically, I intercepted the signal from the oil pressure switch to the ECU and tapped it to the wire going to the tachometer warning light. Basically, if the warning light "sees" ground - the oil pressure light comes on (the yellow side is hot). Knowing that my switch provided ground when the engine wasn't running, the intercepted ground signal was enough to light the oil pressure light at the 'on' position. I cranked and started the engine - and the oil pressure light went out. That's because my switch goes 'open' when there is pressure. My hunch is that other 2004 F50 and F60s are similar.

I didn't feel comfortable completely stealing the signal from the oil pressure to the ECU - that's why I tapped into that signal instead. So, the ECU sees exactly what it saw before. So, if this engine does have 'limp home' mode (does it?) - then the ECU still sees the signal change. But, that also assumes that the ECU sees 'ground' as a problem as opposed to 'open' - which conflicts with the manual.

I've found at least 3 other errors in the schematics for the service manual - so I'm fairly confident that this is yet another error. But, if someone wants to make this definitive, measure resistance between ground and the lead on your oil pressure switch and post the results. My hunch is you'll have continuity when your engine is not running. Let us all know!

Love this outboard!