Yanmar tachometer

[foster]

Hello,

I noticed that the Yanmar tachometer  sometimes gets irrealistic readings. I guess it's a false contact somewhere. After this it went back to normal by itself.

Has anyone an idea how to fix this ?

[Bruce Bogdanoff]

The Tach generally gets its readings from the alternator field output. You most likely have a loose or corroded terminal there or on the back of the tach. Check the manual for the color of the wire and the tighten each end of the wire or better yet, remove the wire, emory cloth the stud and the ring, put some NoOx on each and retighten. That should solve the problem. 

Bruce

[foster]

Thank's for this advice, I will check all that soon.