Tach reading high - 98 Ski Nautique

[east tx skier]

Got the boat out for the first time this weekend. Over the last few weeks, I have had installed a new depth finder and clock as well as a battery switch. When I got on the water, I quickly noticed that my analog tach was reading about 800 rpm high at idle and at speed. The tach on my Perfect Pass gauge seemed to be right on the money.

Any ideas on what could be causing this and possible solutions?

Thanks.

[bchesley]

For a cause, coincidence! Solution, possible ground on the guage maybe? If the PP is reading fine its just the guage.

I can't imagine anything you had installed could any direct effect on the tach.

[east tx skier]

Yeah, my guess is the gauge, which kind of stinks because those downswing tachs don't appear to be available anymore.

I didn't figure anything that was installed is conflicting. But just thinking back to a last known good configuration, that is the only thing that has changed since the last time the boat was running.

When I first started it, the analog tach went full circle, pegged itself, and came back down to about 1,400 rpm while the PP tach was idling just under 700 rpm or so.

[east tx skier]

Reading a little more, looks like I might have some success with flipping the switch on the back of the tach between 4 cyl, 6 cyl, and 8 cyl a few times to clean it off. I'll report back if this helps.

[east tx skier]

Flipping the switch n the back of the gauge back and forth a few times worked like a charm. RPM gauge was spot on today.