Tach wiring?

[ogishere]

Can anyone tell me how to wire this tach? It came off a 1978 70hp Johnson the face says airguide and it has a black wire a yellow wire and 4 screws labeled 1-4 number one and two are bridged together with a red piece of wire. It is the original tach for this motor. I found the gray wire for tach signal in the control box just do not know where to wire it.

Thanks for any help

 

[iwombat]

Re: Tach wiring?

I have one of similar vintage, mine only had two wires. Yellow to grey sending wire, black to ground. Try that first. If that doesn't do it, you may need to hook up a +12v to one of the other screws.

 

[ogishere]

Re: Tach wiring?

I will give that a try hope it works!!

Thanks alot!

 

[iwombat]

Re: Tach wiring?

No problem and good luck. Let us know how it works out.

And welcome to iboats.

 

[ogishere]

Re: Tach wiring?

Worked like a charm!! black to ground yellow to gray signal wire I dont know what the screws are for. Doesnt matter as long as it works right!

Thanks again!!
ogishere8)

 

[imported_airxsteel]

Re: Tach wiring?

The others may be for a back light?

 

[iwombat]

Re: Tach wiring?

on mine the light is a removable socket with its own wire.

 

[ogishere]

Re: Tach wiring?

should I try hooking power to the screws to see. I dont want to burn anything up! I have worked on this boat for months now with my 11yr old son if I mess it up he would be a bit upset! He is pretty excited about its first day on the lake, hopefully this weekend depending on the weather.

Wish I would found this board about 6 months ago!!
thanks alot
ogishere

 

[iwombat]

Re: Tach wiring?

I have a spare. If you burn it up, I'll ship you mine.

 

[ogishere]

Re: Tach wiring?

I appreciate that I will try it this weekend gotta work the rest of the week!

see ya later
ogishere

 

[Seasport]

Re: Tach wiring?

I would leave well alone if it is working OK. It may not need a separate 12V connection. The screws and wire bridge between them may be related to setting the tach to match the number of poles on your stator windings (which vary from motor to motor). Does it have a separate little rotary switch to set this (normally set to 6P for larger sized Johnsons)?

Putting 12V blindly on the screws may not be good for the tach!

 

[iwombat]

Re: Tach wiring?

That's probably good advice. Is there even a light socket on yours?