Tachometer, Alarm and Engine Hour Gauge

[Mark]

I have a Hunter 31 (1986) and I have a few issues with my gauges and alarms. The alarm that should come on when the key is turned on does not work. My engine hour gauge does not work consistently which I think is associated with the tachometer not working all the time. To get it to work sometimes you have to rev the engine and then it starts working. I am thinking that somewhere in the system there is corrosion or a sending unit is not working. I base this on a conversation I had with my mechanic. Has anyone experienced any or all of these problems? If so is it something I can do myself or should I have the mechanic work on it? By the way the engine is the Yanmar 2GM20(F). Appreciate your insights.

 

[William Berson]

Ground Round

Check the grounds, especially at the main panel or grounding buss bar. The 2GM can have vibrate a lot at times, which in my boat resulted in an intermittant ground lug connection and all of the same symptoms you report. Adding a stainless lockwasher and tightening all the ground connections solved the problem. If you lose the main ground connection, you will also probably blow the alternator diodes, so don't ignore this one.