The Genesis Mikado has a MAJOR problem with a flimsy connection on the two electrical connectors attached to the weight halves under the cab. This causes the stuttering and stalls under finally one or both break off. I recommended in my repair article below that EVERY model be corrected and probably the Hudsons too.
The Athearn repair servive either overlooked the bad connections or just reconnected the wires to new connectors which will soon break again. It is necessary to ditch the connectors, strip the wires longer and wrap them directly under the bolts with washers. All details below included disassembly instructions. Not as difficult as it looks.
Robby