Have 06 56 voyager. The gauges on the bridge intermittently go dead they will spike the digital rpm readout will read continuously incorrect numbers. Seems to happen after running for an hour or so. Any ideas?
If all of the gauges react at the same moment, I would look for a common grounding problem. Since it happens after an hour of running, its likely a connection in the engineroom that fails related to heating/cooling. It's perhaps a place to start looking.
If your engines are Volvo D12 675hp, On an '05 56 I ran there was a sequence to turning the keys on. If you turned the wrong key on first (sorry don't remember which one) the digital tach gauge would show funky characters and there would be a whistling noise. Carver or Volvo told us they installed a diode to prevent current from back feeding between the ignitions (??) Sandy destroyed that boat and it's been a long time since I was on that one. But Mike Osmanski at Marquis / Carver might be the guy to talk to. There was also a software update to correct a "Miss" at 2050 rpm. IF you didn't get that check with your Volvo dealer.....and pay very close attention to the wet and dry exhaust elbows. If it happens consistantly after an hour it could very well be heat related.
Capt. Thank you for the input. I am thinking it may gave something to do with a relay on the bridge that the gauge wires run thru. Apparently there is some process where carver converts the digital information sent from the evc to analog.
It could be the gauges also. The factory carvery gauges are made by Faria, which don't last long and do things like you're describing when they're going bad. They're also an odd-ball size so you have to replace them with Faria gauges again.