Based on the powerhead photo, 4 hp, ’31 or later, but not so late that it had the internal rotary valve. Port cylinder is shot, carrying handle is broken off. From what I can see of the lower unit, there is no anti-cav plate, which makes it a Sea King. The motors with Evinrude or Elto on them had the plate. The muffler and lower unit with the underwater exhaust tube makes in post ’31.