1997 Force 75hp not charging battery

[LS3to302]

I've done quite a bit of searching on here. I had two batteries ran parallel and read that the charging system isn't strong enough to charge two batteries. So I went with a single battery. When the boat is off, the battery is showing 12.5V. When the engine is turned on and ran up to around 2000 RPM the volts jump all over the place from 5 to 14, using a multimeter for my readings. Is this normal? Would this be a rectifier or a stator?

 

[glenn property of pam]

might be the meter. some cheap digital meters struggle with pulse dc and will throw strange readings. Turn the meter to ac and tell us what the meter reads

 

[LS3to302]

I think you may be on to something. I haven't done as you suggested yet but I did the following. I tested battery voltage before running the motor at 12.3V. I then ran the boat for 5 min at 3000 RPM and turned it off. The after battery reading was 12.6V, this suggests that it's charging correct?

 

[glenn property of pam]

sounds about right. see if anyone you know has a old fashion needle type meter and borrow that as they don't care about the chop in the dc