Tachometer question

troyl

Cadet
Joined
Jul 26, 2008
Messages
12
I have a 1981 Bayliner with a mercruiser 5.0 engine so when i turn the key on the tach pegs out and with key off goes to 0

Thanks Troy
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Tachometer question

Hi Troy,

We need a bit more info mate.... Is the boat new to you? Has the tacho been working and has suddenly stopped? Have you been changing any wires at the back of the console or in the engine? What year is the engine (not the boat, the engine)?

Chris........
 

troyl

Cadet
Joined
Jul 26, 2008
Messages
12
Re: Tachometer question

The engine is also a 1981 and no i have not been messing with any of the wires in the back but it is possible that the previous owner did and also I have only had the boat a few weeks and the tach has been doing the same since i have had it
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Tachometer question

So, the boat's new to you.... Check that the wiring to the tacho is correct. Positive to positive, check that it's grounded correctly, and the signal wire is in the right place.

Chris.......
 

troyl

Cadet
Joined
Jul 26, 2008
Messages
12
Re: Tachometer question

so which wires is it i am looking for (colors) coming from what to what
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Tachometer question

The back of the tacho will have 3 connection posts... A ground(negative) which will have a black wire on it. A power post, which should have a white wire.. and the signal should have a brown wire.... This all assumes that the wiring is still standard....

Chris.........
 

troyl

Cadet
Joined
Jul 26, 2008
Messages
12
Re: Tachometer question

so what about at the engine also color of wires and going to what I might as well check both ends
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Tachometer question

First check you have power to the tacho and a good ground... The signal for the tacho comes from the -ve side of the coil.
 

chrisg

Chief Petty Officer
Joined
Jun 29, 2004
Messages
476
Re: Tachometer question

Ha, my Tach is starting to having the same issues, maybe this is a bayliner thing, does your tach have letters US on it? If I smack mine, the needle goes to what appears to be the right spot untill the next bump). I checked my connections and they are tight. Does smacking the gauge make it work?

My voltmeter also quit. It may be the gauges.
 
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