Is it possible to hover a 4*40 with a GMS .47?

Sure but it will not be easy. Move the cg back a ton and get as much throw as you can and sure, why not.

Be careful with the CG on the 4star! 1/4 inch or less at a time:-) The 4Star has a higher aspect wing than most 40 size 3D aircraft, where you can get away with large CG changes. But sure U can hover the 4Star on a GMS.47 if not too heavy. (4.5-5.5lbs is good). When the motor is fully broken in try a APC 12.25X3.75W prop.
Like DA KING said " It will not be easy" Happy Flying all