1996 Merc 150 EFI Voltage Regulator?

I have a 96 Merc 150 EFI that I am having some issues with.

When I am running the boat, especially at lower RPM, the tach is jumping all over, the motor isnt reving with the tach. This weekend, running at 1/4 to half throttle, it would occasionally lose power for a few seconds and then come back up. Full throttle, everything seemed good. I think I may have voltage regulator, stator issues.
Does this sound like the problem, can I purchase these parts and install them myself or is the install pretty involved.

[Dden]

I had same issues with 96 Merc 175 EFI. It was the voltage regulator, but I did not do the replacement myself.