With two years passing, I would assume that you may have found out as to the fuse location on the satoh S650G tractor. Just in case.... the two (2) main fuse holders are located up under the dash. They can be reached from below to the left hand side of the voltage regulator. These fuse holders open by screwing the top half off (they are threaded). Each stock fuse holder contain a 10 amp 7/8" long glass buss type filament fuse.
Be aware that these fuses are a little hard to come by especialy in the 10 amp range. The newer 1 1/4" fuses will not fit in these holders.
Good luck!!!