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Alternator output drops when rev'ing up.

F

Floatation Device

Contributing Member
Have a 1996 SeaRay 330 with twin 7.4's. On the starboard engine, at idle, alternator output is 14.5 volts on the cockpit gage. When I rev up, the voltage drops below 10 volts. I noticed the RPM guage also reads high varing between 200 to 500 RPM higher than the port engine. The balance gauge shows engines are running equal. any ideas?
 
To confirm your issue you need to put a meter across the battery terminals (digital hand held volt meter prefered set to 20 volts minimum) and see what voltage at what rpm you realy have.
 
Found 13.5V at the battery. Checked the Alt ouput at the rectorfiers on the bulkead and output is 14.5V. Voltage at the dash gauge is reading correct as the voltage drops. Tach is also irratic. Will check the engine harness connection, clean, and spray in some corssion X.
 
Floatation Device said:
Found 13.5V at the battery. Checked the Alt ouput at the rectorfiers on the bulkead and output is 14.5V. Voltage at the dash gauge is reading correct as the voltage drops. Tach is also irratic. Will check the engine harness connection, clean, and spray in some corssion X.
Click to expand...
Good place to start..... Check all grounds, too.
 
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