Trouble after low oil alarm 50 HP 2 Stroke

[preciadoPontoon]

My 50HP Mercury 2 Stroke outboard motor has been stalling and not exceeding 4500 RPMs after a low oil alarm. I had the motor at full throttle when the 2 stroke oil ran low and sounded the alarm. There was still oil in the reservoir. I refilled the oil reservoir and since the motor has been idling rough, stalling at low (idle) speeds and not exceeding 4500 RPMs. The boat runs good at the 4500 RPMs but has hardly any power. Any suggestions on the problem? Any help would be greatly appreciated!