question about T Bolt tacho

[dungbeetle46]

I have a 1500 merc with thunderbolt ignition, have picked up an original T Bolt tach with no wires connected to it.
I know that
Brown is signal
white is 12+
black is Neg
what I dont know is where they connect on the rear of tacho
the back has a + and - which I presume is white and black but where does the brown wire go to
Thanks

 

[emckelvy]

Re: question about T Bolt tacho

The original Thunderbolt tachs ran off the switchbox. Note that if this is truly one of those, it will not run properly off the signal from the rectifier, only from the CDI box.

This diagram should help:

http://www.maxrules.com/oldmercs/Wiring/1966ona/35.jpg

Cheers.........ed

 

[dungbeetle46]

Re: question about T Bolt tacho

Thanks Ed, but that one only shows the wires going to motor and controls and from controls, I need where they go once they arrive at the rear of the tacho.
On the rear of the tach it has a pole with pos+ and a pole with neg- and then 2 poles for mounting, where does the signal wire (brown) connect on rear of tacho?

 

[dungbeetle46]

Re: question about T Bolt tacho

added pic if that helps

 

[Laddies]

Re: question about T Bolt tacho

I think the top wiring diagram is what you need.

 

[dungbeetle46]

Re: question about T Bolt tacho

thanks laddies thats the one.
rescued again
cheers