I/O Tach Not Working

[atx111]

Picked up a '78 Cobalt 19' BR a couple months back. It's in fantastic shape for its age and everything checked out with the mechanic I took it to(except the tachometer). When I turn the key to start the boat, the needle bumps up just a little, but thats it. I'm thinking that its getting power, is it just a bad tach or could there be something else not right? Thanks for the help!

 

[Silvertip]

Re: I/O Tach Not Working

Do the obvious. Check connections on the back of the tach to ensure they are clean and tight. Next check for +12 volts and ground (the terminals are marked). The "S" (send) signal comes from the engine ignition system. Check the engine connection (at the coil). The wire will likely be the same color there as it is at the tach.