Tach not reading

[Anyox]

I have a 1982 Johnson 90 HP v4 and the tachometer has stopped reading on the dash. I have begun going through the repair manual to track down the problem, but haven't yet been able to figure it out. Other symptoms are that the trim gauge is no longer reading as well. I have replaced the rectifier as a first cheapish solution, but that wasn't the problem. I am currently thinking that it is either the voltage regulator or possibly the tach itself. How would I tell the difference between the two? Also if anyone has a picture or knows the color of the wire from the tach that would be helpful. My manual tells me to disconnect the tach, but I don't know which wire it is and there are many wires coming from the area of the flywheel. Thanks!

 

[countvlad]

Re: Tach not reading

I have a 1982 Johnson 90 HP v4 and the tachometer has stopped reading on the dash. I have begun going through the repair manual to track down the problem, but haven't yet been able to figure it out. Other symptoms are that the trim gauge is no longer reading as well. I have replaced the rectifier as a first cheapish solution, but that wasn't the problem. I am currently thinking that it is either the voltage regulator or possibly the tach itself. How would I tell the difference between the two? Also if anyone has a picture or knows the color of the wire from the tach that would be helpful. My manual tells me to disconnect the tach, but I don't know which wire it is and there are many wires coming from the area of the flywheel. Thanks!

if you have the manual then theres a diagram of your motor and igntion system....

does you battery charge? do you have 13.5V at somewhere above 2500RPMS?

have you tried this???

if you have a 3 wire rectifier:
http://forums.iboats.com/showthread.php?t=190638


if you have a water cooled rectifier:

http://forums.iboats.com/showthread.php?t=190636

 

[Anyox]

Re: Tach not reading

I've been trying to understand the wiring diagram and have been able to read much of it, but have not been able to figure out all of the components on the diagram. The battery is charging very well at I think 13.54 V. When I connected the voltmeter to the grey terminal it was reading about a volt low. (I'm sorry...I don't have the manual right next to me at the moment so I can't tell you what that was exactly).

As I said, I have replaced the three wire rectifier about a year ago as a first fix to this problem. If it helps in the diagnosis, the tach guage seemed to die intermittantly....meaning that it began reading oddly on occasion, but this became more steady before finally not reading at all.