Intermittent tacho & engine hours meter

[MikeBz]

We have a Perkins Prima M50 and Perkins control panel. The tacho has been intermittent all year, generally not working. I wasn’t too bothered as I can roughly guesstimate revs by sound and speed through the water, but it seems this also affects the hours meter. Connections at the alternator look OK. The panel is removable but bedded with sealant, so before I remove it to check the connections at that end does anyone have any suggestions?

Is the hours meter driven from the tacho signal and if so how does that work?

 

[Boater Sam]

Hour meter is usually driven by the ignition, it will count up even without the engine running as long as it has power.
So its probably a bad connection to the tacho pos or neg.

 

[Ray Purchase]

Does the back light work at night?

 

[MikeBz]

Does the back light work at night?

Good question - I will check next time I’m on board at night!