[Bassmiester51]

I had a similar problem on a 2001 Jag, 225 Yamaha. The tach was reading all over the board, I replaced the Voltage Regulator, No problems after that. Good Luck, Hank

[Bassmiester51]

I dont recall the Tach not returning to “0” when the engine was shut down, but the Speedo would register while not moving when engine was running, and that problem also stopped when regulator was replaced. May not be the same as your Problem, But should not be a problem to replace on a Merc vs. Yamaha which I have. Got to start somewhere! Hank

[Bassmiester51]

Im not positive, But I belive the Lowrance units need to be wired through a Master Power switch, so that when power is shut off the internal power at each unit is completly OFF. Just a thought. Hank

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