Bought a boat and the tach wasnt hooked up. Need help

[Burns363R]

I bought a Celebrity 22' boat with a 5.8 volvo in it. The wire that goes from the tach to the coil was unhooked at both the tach and the coil. When i hooked them up (obviously something is wrong with it) the tach will move slightly when the engine is idling, but when i rev it up, it doesn't seem to move at all. I mean it moves, but only a few RPM,

I would assume the tach is bad, but i wanted to check first. Is there anything else that could be wrong. What all wires on the back of the tach need to be hooked up for it to function? There is another purple wire with an eyelet near by it that isn't hooked to anything. I believe the tach has an open terminal called signal on it. I hooked the gray wire from the coil to the terminal that said ignition.

Thanks

 

[Burns363R]

Maybe i have it wired wrong. Looks like the purple is the 12v power that should come from the key. Looks like that should be hooked up to the terminal that says ignition. The gray wire from the ignition needs to go to the signal terminal. I will try this and post back.

 

[Silvertip]

What you said in your last post is correct. But do not ignore the ground connection. All connections except for "L" (internal light) need to be connected for the tach to work. If there is a 4-6-8 selection then that needs to be set to 8. You might move that selector back and forth a few times to burnish the internal contacts as they can be troublesome if slightly corroded.

 

[Burns363R]

Well i switched the wires to the way i said earlier and Wola, it worked fine. I did notice that my setting on the back of the tach was at 5???? I saw a 8cylinder 4 pulse options,

Anyways, the boat idled at 600 rpm on the current setting.

 

[Burns363R]

I find it odd someone would unhook the tach at both ends???? Im still leery of to why they actually did this. Im assuming a problem will show its face at some point.

 

[Silvertip]

You have an 8 cylinder engine. 8 cylinder engines deliver four ignition pulses per engine revolution. Set the switch accordingly.