Where do I start?

[mphy98]

Ok I have a 1991 Starcraft superfisherman with a 1984 merc 135hp on the back. The tach does not work. I know this is asking a lot but where do I start with this, and how do I test for anything. Should I get a new gauge and start there? Any help, major thanks.

 

[sw33ttooth]

Re: Where do I start?

well first off when you turn the key from off to on does your tach pick up a little bit or stay flat lined? and wondering if its lighted does the light work? just seeing if you got power to it before you start buying stuff you dont need. if it doesn't have power i'd look at the back of the gauge weather you can pull the dash out or look under make sure that there are no wires disconencted to it. to my tach i have;
purple = ignition +12 v
blue = lights
black = ground
sending wire = forgot color...
and a few other wires grounding other stuff and a beeper when i turn key on.
then if all that checks out i would look at the sending wire from dash to the wire harness that runs to the motor. make sure its not cut and grounding.
if all that is good then from where wire harness plugs into your outboard i'd find your sending wire[ SHOULD BE same color as it was at dash.
make sure its attached to what it's suposed to be.

if for some reason all that looks good then i would find a new tach doubtfull its accually the gauge but could be.
i just put a 7 set into my four winns sundowner 2 weeks ago of course they were all working before i did that so it was easy.