volvo penta 8.1 alternator issue.

[Jerrell]

I have a volvo penta 8.1 engine, and im having alternator trouble. I have a 140 amp alternator with an external regulator which have been checked out to be good. However the main two batteries will not charge up when operating the boat. Just trying to discover where the problem is. I have been told a Volvo Penta motor has to have a volvo alternator. The one that came on the boat is a GM 140 amp high output. Any advise or experience on this problem will be welcome.

 

[omc_10]

how much horsepower does your engine have?

 

[el_pescador]

I have been told a Volvo Penta motor has to have a volvo alternator.

This is simply not the case. However, you are not providing much information to help you troubleshooting the problem. I would start checking that the alternator is charging when the engine is running (voltage should go to 13-14 volts or even higher) and make sure the output from the regulator goes to the batteries.