Dabooo, the powerhead parts are still readily available from Bombardier, the guys who bought OMC. If ya take a copy of the parts manual to a friendly Johnson/Evinrude parts guy..go at a time when no one else is there and bring him a coupla doughnuts... he can probably cross reference the part numbers you have to current parts.. It may take a while to get.. but they are mostly available.. I think that the lower housing/gearcase may not be available, but most internals will be.. Happy Hunting !
EDIT: I think they are based on a 35 HP, 2 stroke, twin block .. The engine has been "de-tuned" a good bit for good torque and long life.