volt gauge on dash..

[HickoryJim]

Last night when I took the boat out for a short sunset view, I noticed the volt meter went flat (needle at 10) and yet after about 20 minutes it started climbing making it up to almost 13 by the time I returned...I let it idle at my dock for a while but it never got past 13. I checked the belt...tight. All other electronics working...no problem starting (single battery, new this spring).

I'm not engine smart, but enough to check some things out if any of you can suggest where to start other then with the local Mobile Mechanic$. I did check the wiring behind the gauge, everything was tight. All electronics were working as normal (lights, GPS, stereo, etc) and engine running smooth.

Your ideas/suggestions would be appreciated.

2004 Maxum 2200
Hickory North Carolina

[jparsons121]

Verify that the readings you see on the helm gauge are actually correct.
Measure the voltage at the battery at rest and with engine running.

[mmwjr]

Agree with jp, first verify if the voltage at the batteries and alternator are holding at ~13.5 V with the engine running. If not the alternator may be faulty or you have a loose or corroded connection somewhere.