[C320-list] Tachometer Issue

[Crosby Roper]

Hi All,

My tachometer is non-responsive. The needle is is stuck at about 1000 RPM and does not move at all. The unit is also not recording engine hours. I pulled the panel to check connections. everything seems to be in order there. I have a Yanmar 3YM30. I need some guidance on trouble shooting. I've checked for the sending unit but can't identify it. Is it on the alternator or the fly wheel and what does it look like? Would it help to put an ohmeter on the tach to see if it's getting power? I'm an electrical ludite, so the more guidance someone can suppl the better. I had this happen a couple of years ago and the local yanmar service just replaced the Tach unit. Does this sound like a power/sender/sensor issue or is the tach itself bad? Thanks for assistance in advance.



Crosby  Roper VMD
s/v Tethys; Hull # 1054
San Diego, CA