High reading on dash Voltage indicator

[drumcutrer]

Hello folks of Club Sea Ray, Always appreciate the advice of all here and wanted to get your thoughts on an issue I had yesterday with my 2001 Sea Ray 290 Amberjack. Was cruising the river for about 30-40 min and after getting up on plane, noticed the my port voltage indicator was showing 15 to 16 volts and the needle was bouncing erratically. Temps and oil pressure was fine. Within a few minutes the port engine died and I could smell fuel. I backed down the starboard engine and hit the blower and motored to a spot to inspect the engine. Didn't notice anything unusual, except that the serpentine belt on the port engine was a bit loose. Tightened it up and also checked for any loose wire connections. Again nothing really caught my eye, and decided to enjoy the anchorage there, and had lunch with the wife. Headed back to the slip with both engines, running on plane. Port voltage indicator is holding steady around 13.5 and after about 5 mins, starts jumping erratically again in the 15-16 range, then within a couple of mins, dies again. I motored back on the starboard. The engines are 2001 Mercruiser 5.7 MEI carbureted. Seems like an electrical issue; would it be a coil heating up? Voltage regulator, loose ground ? Any help is greatly appreciated! Thanks, D Cutrer
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2001 Sea Ray 290 Amberjack Lady Madonna, 2004 Sea Pro SV2100

 

[Strecker25]

Check your main lugs at the engine, the starter positive and the ground. I had an issue in our last boat where voltage shot up and it was because the positive lead to the starter was progressively loosening up. As it lost good contact the alt had nowhere to output voltage and the ECU would shut down from over voltage condition. We had similar engines, 98 5.7EFI’s

 

[drumcutrer]

Thank you for the reply. I'll check that out.

 

[northern]

Our jetboat with a 5.7 will charge at 15 almost 16 volts when starting out in the morning then drop to 13 to 14 after an hour or so. We run it at 3 to 4 thousand RPM. I assume it is due to us using the batteries at night for light and to charge things. We have a dash volt indicator and a volt read out on the depth/navigation screen. Needle does not bounce. Hook a multi meter to a 12 volt device like a light and if it is solid reading you may need new dash gauge.

 

[drumcutrer]

Thanks for the reply.