One of my tachs reads off by 500-1000 RPM (low). The Smartcraft displays correct RPM. I've switched tachs and it still reads low on the same side so it's not the tach.

Any thoughts/suggestions? Thanks

If you switched tachs and used the same wiring on the left side, it could be a bad ground.

I'll check the ground but don't think it's the problem. I also have a Livorsi Data Tach that has dedicated power and ground and shares the tach signal. It also reads the same (low) rpm on the starboard motor.

Something is causing the (analog?) signal to be off on that engine.

Thanks

The tach needs to be re-calibrated. Call Livorsi.

Dave

Will a bad AGI Box cause this or do they just totally crap out?

In my experience - the AGI's just crap out - either in or out - no half a$$

Sorry, I missed that. Maybe the Analog tach is back feeding the data tach. I don't know if there would need to be an isolation between them. Did this just develop, or has it always been this way?

I'd still call Livorsi.

dave

AGI box will cause that.

Thanks, ordered one. I'll post how it works out.

new AGI box fixed it