1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

[endurance]

All terminals on switchbox check out ok according to cdi troubleshoot guide. Except for green terminal Not getting the 100volt on green terminal I have no voltage. Bad switchbox or something else heads up would be great! Thanks all

 

[Chris1956]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

I would think that the coil will only get voltage when the trigger fires the switchbox. The spike may be to quick to see on an analog meter.

 

[endurance]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Thanks for the reply. I used a fluke digital. It gave me
All of the readings accurately where they were supose to be
Accordong to.cdi.

 

[Chris1956]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Well, if you crank it, with the meter attached to the green teminal on the switchbox, do you get any reading? Are you using the AC or DC setting?

 

[endurance]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

No reading at all while cranking.motor while making
Contact this meter is set to read volts it gave me all of the
Acurate volt readings on other terminals

 

[Faztbullet]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

If you have no voltage output on green wire you have: 1) defective switchbox (which I doubt).. 2) trigger is not firing switchbox.. 3) mercury switch has switchbox grounded

 

[endurance]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Mercury switch? What is that amd where is it located

 

[Chris1956]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Mercury switch is usually located on cowling support, near switchbox. It is a blue plastic thing that looks like a condenser.

 

[mercurymang]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

I think we have the same motor. Does your's look like this? The wire that is cut went to my mercury switch.

 

[endurance]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Exactly the same. i will disconnect it and see if i get spark.
Thanks so much merc mang for the heads up.

 

[mercurymang]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Cool beans although Chris should get the credit for that. BTW. I was looking at the wiring diagram. Does anyone know what the white wire is for?

 

[Chris1956]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

In that vintage motor, white is usually+12VDC from the ign switch. You would need to look at the correct wiring diaghram, likely avail at the maxrules web site.

 

[mercurymang]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

When you were checking the voltage on the green wire, were you checking it with it attached to the switchbox. Technically what is occuring is the leg on the switch box for the green wire provides the ground for the coil causing the field collapse in the secondary. If that wire is not hooked up, you will get no voltage.

 

[Faztbullet]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Coil is already grounded as the green it the input... this is not like a automotive ignition.

 

[endurance]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Ok removed the white and Black wire from terminal
as well as the blue and Black wires from their perspective
terminals. jumped the white and Black wire with the
black wire. connected a switch to the blue wire. then
hooked up a spark tester to the wire coming from the
coil (the one that goes to the distributor).turned the key to the on position Hit the switch on the
blue wire ; finally fire. spark lighting up the spark tester .
Now this is what is suppose to happen when the
black and white,black and blue wires are hooked up from
the distributor . Anyone know why the distributor is not sending this signal to the switch box
thanks for the heads up

 

[Faztbullet]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

The distributor is bad from a internal failure or belt that turns it is broken. Usually they fail due to the insulation falling off wires and they short or battery disconnected while running..

 

[mercurymang]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

Coil is already grounded as the green it the input... this is not like a automotive ignition.

So does it have points then? How does the primary dump it's current?

 

[Faztbullet]

Re: 1975 mercury 65hp 3 cylinder no voltage on green wire from switch box

So does it have points then? How does the primary dump it's current?

Does not have points and coil is idle waiting on voltage from switchbox to + side of coil, the - side of coil is grounded to block.