93 yamaha analogue tach

[Dunaruna]

1993 Yamaha 70BETO.

I need to make a new loom from the engine to the oil warning lights in the yamaha analogue tach (the loom is missing). In the engine mounted oil tank, the 2 wires from the oil level sender are green and green/red (green/red is split into 2 so there is actually 3 connections). At the tach I have green, yellow and red (and black ground) going into a 4 pin plug that is not connected to anything.

How does the oil sender connect to the 4 pin plug at the tach? The genuine manual does not cover this (unless I have missed it somehow).

 

[erniefish]

Re: 93 yamaha analogue tach

i think i have one collecting dust in the garage, i will look,you can have it ,if you need it ,let me know e

 

[Dunaruna]

Re: 93 yamaha analogue tach

i think i have one collecting dust in the garage, i will look,you can have it ,if you need it ,let me know e

That would be fantastic, yes please.

 

[ruffinit]

Re: 93 yamaha analogue tach

I have the same issue. I bought the wiring harness for the trim gauge/oil lights, but the four-pin plug for the oil lights has only two wires at the engine side (green & green w/red stripe). That still leaves me with a yellow w/red stripe wire (and a black which I assume is ground?) at the gauge end that does not connect to anything.
Also, coming off the oil level sending unit, there is a black wire with a ring connector, which is not connected to anything. I assume (?) that this is also a ground?

Can anyone help straight this out?

 

[Dunaruna]

Re: 93 yamaha analogue tach

Yes, the sensor black is ground, it goes to the engine block. The black in the 4 pin plug is also ground.

This is how (i think) the system works - When the oil is full, the oil level sensor grounds out the green wire, this tells the CDI unit to turn on the full light (also a green wire). When the oil is near empty the sensor grounds out the green/red wire, this tells the CDI unit to turn on the empty light (red wire). When the oil is about a third full, no wires are grounded, this tells the CDI unit to turn on the middle light (yellow wire). The empty signal also triggers other safety features such as reduced revs and audible alarm (pink wire I think).

The problem is, I cannot find a wiring diagram for the section between the motor and the tach. Somehow, the CDI unit is involved in this scenario but I don't know how. I suspect ANOTHER auxiliary control box is involved which would be included with the now obsolete warning light harness. Maybe it is inside the 703, dunno.

 

[ruffinit]

Re: 93 yamaha analogue tach

Thanks for the reply. Your explanation makes sense to me, but I am still not sure why this is not "plug and play". First, I was going to simply make a wiring harness from motor to gauges, as well, but I could not find a motor side wiring diagram, either.
So, I bought the oil/trim wiring harness, but it still leaves me with the yellow wire from the oil lights connected to nothing....
One more, (maybe dumb!) question. When I turn the ignition ket to "on" before cranking, is the buzzer supposed to sound?
I thought I had thisissue correctly figured out when the buzzer sounded, but as soon as I went to "crank", I blew the fuse at the motor. That's when I gave up.

 

[Dunaruna]

Re: 93 yamaha analogue tach

I feel your pain, I am still at a lose as to where the yellow wire connects but I'm not giving up - just yet.

 

[ruffinit]

Re: 93 yamaha analogue tach

I am going to stop at my nearest dealer in the next few days. I have found the secret is to get there early, when the mechanic is opening up,before the salesman gets in. the mechanic is pretty helpful, and much more likely to give advice, rather than say "bring it in, we'll have a look at it".

 

[ruffinit]

Re: 93 yamaha analogue tach

I visited the mechanic at my local dealer. He xeroxed the page from the yamaha rigging guide, which indicates that the yellow/red wire goes to the yellow (+) wire on gauge harness from control box. This makes no sense to me, since it seems this wire simply supplies 12v whenever ignition is "on".
I admit I am no electrician, but should this be so hard?
I may just give up on this and take it in to the dealer to sort out.........

 

[Dunaruna]

Re: 93 yamaha analogue tach

This might make sense, the lights have constant 12v but the switching on/off is controlled via the ground. The ground is controlled by the float switch in the oil tank (via the green, green/red wires). Does this mean that the red from the 703 goes to the 4 pin plug on the tach?

Could you post the diagram?

 

[ruffinit]

Re: 93 yamaha analogue tach

Will try to post rigging guide. I don't knnow how legible it will be. If you PM me, I will attach a better (larger file size) copy.
Here goes.....

 

[Dunaruna]

Re: 93 yamaha analogue tach

That's it! Now just need it a bit bigger and less blurry. You have a PM.

Thank you very much.