kpinnn
Senior Member
For the last two trips op the ICW my port tachs have not worked. They read zero both fly bridge and helm tach. I was told they operated from the alternator. It appears that this is in fact correct. I found a broken wire that once was attached to the port tach. A similar wire is attached to the starboard tach. I reconnected the wire, started the port engine and the tach moved. At this point I figured I solved the problem. Well, not true. hen under way and running cruise RPM's the tach starts to show lower RPM readings. In simple terms the tach will go to around 1400 and then start to go back down while increasing throttle. Also noticed that after shutting down this evening all four tachs show about 1000 RPM's even when the engines are shut down. That is right all four. Can't fault a tach. How does the alternator drive the tach and what could cause a residual indication? What causes the tach to go backwards?
Ken
Ken