In my opinion, the KF5 is a more solid, reliable motor than the Mark five and is much easier to work on. What it gives up in lacking a neutral, it gains in simplicity. Both models have a very sensitive-to-damage gear case. If yours is good (not broken just forward of the prop) treat it like gold and make sure you check/change the grease before and after each use! Welcome to The Dark Side. You have a good motor to start your journey with. They are fast and the run quality is darn near OMC-like. It will, literally, run CIRCLES around a 5 hp JohnsonTD 20.
Long live American manufacturing!