Over voltage condition

"My 115HP 4 stroke has recentl

"My 115HP 4 stroke has recently begun charging at 16+ volts after about 10 minutes of operation (confirmed by separate VOM). It charges at around 14 (as it should) for awhile, then jumps to 16. When it jumps to 16, the tachometer starts jumping around. I think the tach gets its input from the regulater assembly, which also could account for the voltage issue. Before I buy one I wanted to get some confirmation that it was probably the issue. If so, are there any difficulties that I should be aware of in replacing it? Is there any other part or system that likely caused the regulator to go bad, or did it likely do so on its own?
Thanks
Bob"

turn your VOM to a/c volts
st

turn your VOM to a/c volts
start motor
check voltage at battery
if over .8 a/c volts bad regulator

but it sounds like regulator
if under warranty tell yami

I guess that a positive readin

I guess that a positive reading on the AC scale would indicate a bad rectifier----I'll try that. Can you confirm that the regulater/rectifier assembly also sends RPM info to the tach?
Thanks

yes from the green wire

yes from the green wire