switch assembly near the starter solenoid, what is it?

**Aaronhl** · 11-13-2024, 07:38 PM

On the 1991 150 v6 I am working on it has 3 black/yellow wires going from the 8 pin connecter
One wire for each switch box and then the third wire going to a "Mercury switch assembly"
You can see it on the bottom left of this pictures, it is the black cylinder thing...
Never seen it before...can I junk it? Or whats the purpose?

**Aaronhl** · 11-13-2024, 07:40 PM

Also why do the two switch boxes have purple wires coming out of the plastic? Maybe ill have to post a picture of that on the actual motor cuz the one above i got from ebay

**Glastron1987** · 11-13-2024, 09:07 PM

If I recall correctly on some motors, there is a mercury switch which prevents the engine from starting or running when it is trimmed up too high. I think it may have been one of those parts that seemed like a good idea at the time, but in practice was just a nuisance.

**tlwjkw** · 11-13-2024, 09:44 PM

Originally Posted by Aaronhl

Also why do the two switch boxes have purple wires coming out of the plastic? Maybe ill have to post a picture of that on the actual motor cuz the one above i got from ebay

picture? .. only wire i've ever seen comin' outta tha sb casin' was a ground? (black)..

Originally Posted by Glastron1987

there is a mercury switch which prevents the engine from starting or running when it is trimmed up too high.

**Aaronhl** · 11-13-2024, 09:54 PM

Originally Posted by tlwjkw

picture? .. only wire i've ever seen comin' outta tha sb casin' was a ground? (black)..

here is a pic let me know what you think, they both have them

**tlwjkw** · 11-13-2024, 11:44 PM

normal... trigger wires. on a terminal, not coming from plastic/case... tha blacks are grounds...

tha mercury switch can be removed if thats what ya wanna do.. just tape up tha unused black/yellow....

**donmac** · 11-14-2024, 07:30 AM

the mercury switch isn't a nuisance if you make contact with a submerged object snapping the clamp bracket and the motor decides to ride in the back seat with your passengers! I've seen a 235 rude land there when a home made setback broke!
I don't think you can trim high enough to engage the mercury switch it needs to be past horizontal to close! easy to test just unbolt it and put an ohm meter on the leads,turn it upside down and check continuity while changing positions!

**Aaronhl** · 11-14-2024, 10:11 AM

Originally Posted by tlwjkw

normal... trigger wires. on a terminal, not coming from plastic/case... tha blacks are grounds...

tha mercury switch can be removed if thats what ya wanna do.. just tape up tha unused black/yellow....

What do you mean normal? I have not seen a wires coming from the case like this before... so what do I do with it?

**skialot2** · 11-14-2024, 12:44 PM

I always remove the mercury switch. It can cause problems in rough water. I have had it cause the motor to break up and run rough because the mercury bounces around making intermittent contact killing the ignition for micro seconds. Removing the mercury switch solved the problem.

**tlwjkw** · 11-14-2024, 01:51 PM

Originally Posted by Aaronhl

What do you mean normal? I have not seen a wires coming from the case like this before... so what do I do with it?

tha purple (actually called violet in diagrams) stay where they are.. tha blacks need ta be made up under a screw to tha block or any bracket for grounding tha sb's..

they are aftermarket sb's...

**rock** · 11-14-2024, 03:35 PM

I've seen hundreds of switch boxes but never one with a wire coming out of it. I would call CDI.

Rock

**25two.stroke** · 11-15-2024, 07:56 PM

I always hook up that wire coming out of the potting to ground. Seems redundant cause they have a ground terminal also, but that is where it is supposed to go. I have also seen other people put these cdi boxes put in where the wire coming out is run to ground and no wire was put on the ground terminal and the motor still ran fine...so I don't really know why they have both

**tlwjkw** · 11-16-2024, 06:34 AM

Originally Posted by 25two.stroke

I always hook up that wire coming out of the potting to ground. Seems redundant cause they have a ground terminal also, but that is where it is supposed to go. I have also seen other people put these cdi boxes put in where the wire coming out is run to ground and no wire was put on the ground terminal and the motor still ran fine...so I don't really know why they have both

never seen a "ground" terminal on any oem stuff that i remember?.........

**25two.stroke** · 11-16-2024, 12:30 PM

Originally Posted by tlwjkw

never seen a "ground" terminal on any oem stuff that i remember?.........

No it was just the screw on the body of the box. Weird cdi double grounds the box. I ran the blue cdi racing boxes on my bridgeport and they were good. No complaints.

**tlwjkw** · 11-16-2024, 05:36 PM

[QUOTE=25two.stroke;3437033]No it was just the screw on the body of the box.
/QUOTE]

yeah. always 12's or 14's (or latest A number at tha time) for me.. aftermarket weren't big (proven) yet....