Had this happen a few months back while over water in a 206. I reduced power and brought my speed back to about 65 kts, decended to 100 asl, and armed the floats. Checked the MRG gauges, no temp increase or falling oil pressure. Landed in a clearing just after I crossed the beach. Shut down and pulled the plug. Alot of metal. Couldn't quite read the part number on one peice. Overhaul latter found it was a mast bearing if I remember right.
Wasn't there a Puma ditched in the North Sea a long time ago when a MRG chip light came on?
Cheers BigMike