CD 26D - Erratic temp and pressure gauges, maybe alternator?

[rollo_cd26]

Need electrical advice! Recent observations of temp and oil pressure gauges on Mirabile (CD26D, 1988, hull #78) showing erratic movement and trending well past normal readings (185 degrees F, and 55 PSIG) with falling voltage reading 13 down to 11 volts. No alarms from panel for temp or oil pressure. Inspection shows alternator and cooling impellor drive belts are both tight, impellor replaced ~6 months ago, wet exhaust feels about right for 30 minutes of operation, and oil level is in spec. Engine has about 400 actual hours! This has happened twice this summer and gauges will periodically return to "normal" readings then start "flicking" and trending up again. Should I suspect an alternator problem requiring rebuild or replacement, or more sinister ground fault/voltage regulator problems?

Summer on my lake is hot and still, so down time now is actually OK.

[tjr818]

I would suspect a faulty electrical connection somewhere in the circuit, maybe at the instrument panel??

[mgphl52]

I would suspect a faulty electrical connection somewhere in the circuit, maybe at the instrument panel??

Yes, very likely that you have a bad ground connection since multiple gauges are acting up.
Though it could also be a loose positive connection on the panel.