89 mariner 175 tach problem

[pdrguy]

I have a problem with the tach (looks orig) When i turn the key on the back light comes on and it goes to 0 then cranking it jumps to around 4-500 but as soon as the motor starts it goes back to 0 again.
Any ideas? I have checked all conections and all seems well.
Thinking rectifier?
Thanks in advance,
Gene

 

[electricjohn]

Re: 89 mariner 175 tach problem

A tack won't work if the rectifier is bad. If the voltage at your battery is not at least 13.5 VDC with the motor running, time for a new rectifier, or worst, a new voltage regulator (used on higher output charging systems).

 

[pdrguy]

Re: 89 mariner 175 tach problem

Thanks, Ill start there.
Gene

 

[pdrguy]

Re: 89 mariner 175 tach problem

A tack won't work if the rectifier is bad. If the voltage at your battery is not at least 13.5 VDC with the motor running, time for a new rectifier, or worst, a new voltage regulator (used on higher output charging systems).

Thanks John
It was the rectifier